foundationdb/flow/SystemMonitor.cpp

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/*
* SystemMonitor.cpp
*
* This source file is part of the FoundationDB open source project
*
* Copyright 2013-2026 Apple Inc. and the FoundationDB project authors
*
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* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
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* http://www.apache.org/licenses/LICENSE-2.0
*
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* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "flow/flow.h"
#include "flow/Platform.h"
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#include "flow/TDMetric.h"
#include "flow/SystemMonitor.h"
call-site aware memory tracking (#13344) * Initial memory tracking design doc draft, plus first round of review comments by me with // TODO annotations * design/memory-tracker: address first-round review TODOs Resolves all // TODO annotations from the initial draft: - live-block table now optional via MEMORY_TRACKING_LIVE_TRACKING knob - drop the mmap slab pool; std::malloc + in-tracker flag is sufficient - add MEMORY_TRACKING_FORCE_SAMPLE_BYTES so large allocations are always captured regardless of the count-rate sampler - add live block / byte totals to MemoryTrackerSummary - replace the manual coverage spot-check with a sentinel-function unit test that introspects the aggregation table directly - leave ALLOC_INSTRUMENTATION alone; new hooks sit next to (not replacing) existing conditional ones - drop SJLJ jargon, trim A4 alternative now that force-sample-large collapses the byte-rate-vs-count-rate question * flow: add sampled per-call-site memory tracker Adds a sampled memory attribution layer (flow/MemoryTracker.{h,cpp}) hooked into the three primary allocation paths — global operator new/delete, FastAllocator, and ArenaBlock::create — plus a periodic TraceEvent dump driven from SystemMonitor. Knobs gate sample rate, force-sample threshold, report cadence, top-N, and capture depth; prod default is off. See design/memory-tracker.md. Test fixes uncovered while bringing the unit tests up: - memTrackerResetForTest now resets the per-thread sample counter and force-sample threshold. Without this, a test that exercised the off-switch path left gMemTrackerCounter at INT_MAX, which then silently suppressed sampling for the remainder of the run. - Slow-path reseed special-cases inverse==1 to keep the counter at 1. The general formula 1 + r % (2*inverse) yields counter values 1 or 2 at inverse==1, sampling only ~67% of allocations rather than every one, which broke a test that asserts exact alloc counts. - Sentinel functions in MemoryTrackerTest.cpp now route the allocated pointer through an asm-volatile escape() helper. Clang -O3 was eliding the new/delete pair (P0593 heap fusion), so the test's allocations never reached the operator-new override. * design/memory-tracker: address second-round review - threshold-based reporting (80 MB default, ~1% of 8 GB target RSS) replaces fixed top-N - prod report interval 60 s -> 10 min; sim stays 30 s - single combined MemoryTrackerAddrCmd event with one addr2line invocation per dump (positional mapping back to sites), keeping frame 0 — old design's per-site format_backtrace dropped the leaf alloc frame - new R12 "Side-thread coverage" + "Side-thread safety" subsection documenting the FP-elision crash mode found via joshua repros (RandomUnitTests / IThreadPool seeds segfaulted in captureStackFP when walking from FastAllocator<N>::~ThreadData into glibc's FP-elided pthread shutdown machinery) and the stack-bounds mitigation via pthread_getattr_np - R7 wording: live bytes (not cumulative) - CallSite struct in design overview aligned with implementation; ForceSampledCount promoted from prose-only to struct + emitted detail; exemplarFrames sized to MEMORY_TRACKER_MAX_FRAMES (=10) matching the FRAMES knob's stated 1-10 range - LIVE_TRACKING=false degraded-mode interaction documented - stale "slab pool" refs removed (std::malloc was already in code) and fdbserver.cpp self-contradiction resolved - R3 / Rollout reconciled (table shows steady-state, step 1 lands at 0) - 4-6 frame count flagged as initial estimate, subject to refinement - file:line citations stripped from path references (line numbers drift; symbol names are stable) * flow: threshold-based memory tracker reporting + side-thread safety Implements the second-round design changes in flow/MemoryTracker.{cpp,h}, flow/Knobs.{cpp,h}, flow/SystemMonitor.cpp. - MEMORY_TRACKING_TOP_N -> MEMORY_TRACKING_REPORT_BYTES_THRESHOLD (int64_t, default 80,000,000). MEMORY_TRACKING_REPORT_INTERVAL prod default 60.0 -> 600.0; sim still 30.0. - memTrackerDump(int topN) -> memTrackerDump(int64_t bytesThreshold). Filters by liveBytes (or cumulativeBytes when LIVE_TRACKING=false) >= threshold; emits MemoryTrackerSite per qualifying site plus one MemoryTrackerAddrCmd event with a single addr2line invocation covering every qualifying site's frames in dump order. The Summary event picks up SitesReported and ReportBytesThreshold details. - AddrCmd is built directly here (not via platform::format_backtrace, which deliberately drops index 0 for its single-site use case); the leaf alloc frame is preserved. - captureFramesFP gains a per-thread stack-bounds check via pthread_getattr_np + pthread_attr_getstack, cached in TLS. Without it, walking the FP chain from FastAllocator<N>::~ThreadData into glibc's FP-elided pthread shutdown machinery follows an uninitialized saved-FP slot and dereferences garbage. Fixes the joshua-found segfaults on RandomUnitTests seeds 3288611985, 3731245491, and 2219741568 (all in the IThreadPool worker-exit path). See design/memory-tracker.md "Side-thread safety". * flow/MemoryTracker: stub the FP walker on non-Linux pthread_getattr_np is glibc-specific and the macOS build broke on it. Frame-pointer walking on macOS is also unreliable on its own (system runtime has -fomit-frame-pointer in places we can't control), so a "loose bounds" workaround would still risk crashes. FDB is required to compile on macOS but is not run in production there. Gate initStackBoundsForThread + the real captureFramesFP on __linux__; provide a return-0 stub on non-Linux. The rest of the tracker (sample counters, aggregation, dump) still compiles and runs; per-call-site reports on macOS will just lack stack attribution. * flow: clang-format fixup for memory-tracker files Whitespace-only. Catches up flow/Arena.cpp and flow/MemoryTrackerTest.cpp with the project's clang-format style; the original implementation commit (d587f82b) slipped these past the format pre-flight. * edit for clarity, brevity, and uniform voice * flow/Arena: fix double-tracking on the >256/huge ArenaBlock paths ArenaBlock::create's >256 and huge paths go through allocateAndMaybeKeepalive (`new uint8_t[]`), which fires the global operator new[] hook in addition to the explicit memTrackerOnAlloc that fires immediately after. Two sites tracked the same pointer; on free only the explicit-Arena fingerprint was debited, so the operator new[] fingerprint accumulated liveBytes monotonically and LiveBytesTotal/LiveBlocksTotal skewed by +n/+1 per arena alloc/free pair. Reported as B1 in the PR review. Fix at the Arena layer (so non-arena allocateAndMaybeKeepalive callers in serialize.h's PacketBuffer code remain attributed at the operator-new layer): a MemTrackerSuppress RAII helper held across the underlying new[]/delete[] in ArenaBlock::create and ArenaBlock::destroyLeaf. Adds accounting tests for FastAllocator<32>, Arena small, Arena medium (the B1 path), and Arena huge. The load-bearing assertion is "exactly one site has the sentinel's frames AND nonzero bytes" -- fails pre-fix for medium/huge with sites=2. Tests gate on __linux__ since captureFramesFP is a no-op on macOS. * flow/memory-tracker: address PR review follow-ups - Knobs.cpp: sim default for MEMORY_TRACKING_REPORT_BYTES_THRESHOLD drops 80 MB -> 1 MB so sim dumps surface more sites for manual sanity-checking. Prod unchanged. - B2: memTrackerForEachSite holds MemTrackerSuppress across the callback loop so callbacks that allocate (e.g. fprintf failure dumps) don't re-enter tracking under SAMPLE_INVERSE=1. - B8: drop the always-zero g_reentrantBailouts and its SamplesDroppedReentry summary detail. Wiring it would require an atomic in the inline hot path, which R1 forbids. Design doc updated. - B3/B6/B7/B9: explanatory comments only -- frame-strip-count inlining assumption (B3), unstable sort acceptable under R6 (B6), shared xorshift seed acceptable in practice (B7), MEMORY_TRACKING_LIVE_TRACKING is startup-only (B9). * flow/MemoryTracker: one addr2line per site, drop chunking Move the addr2line command back onto MemoryTrackerSite as a per-site AddrCmd detail and remove the MemoryTrackerAddrCmd event entirely. Each AddrCmd carries exactly that site's stack -- short, well under the trace-detail truncation cap, ready to paste. Replaces the consolidated-then-chunked-into-byte-buckets approach, which split stacks across chunk boundaries and made raw events hard to read. * add standard Apache 2.0 license headers to new memory-tracker files The three new files (flow/MemoryTracker.{cpp,h} and flow/MemoryTrackerTest.cpp) shipped without the project-standard copyright/license block. Adds the standard 19-line header to each; file-purpose comments stay below it, switched to // line comments to keep the license block visually distinct. AGENTS.md gains a short "Source File Headers" section so the next contributor doesn't repeat the omission. * address review comments; reduce cost of enable check; maintain net estimates so users dont have to do it manually * formatting * unit test bug fix * gglass review comments on memory-tracker.md design doc * design doc updates, and fill in a plan for remaining tests/benchmarks * delete useless simulation section * flow/bench: add memory-tracker microbenchmarks; record measured overhead Add flow/bench/BenchMemoryTracker.cpp (Google Benchmark) measuring the tracker's per-op cost via three benchmarks -- raw malloc/free baseline, end-to-end operator new/delete, and isolated memTrackerOnAlloc/OnFree -- each at sample inverse 0 / 100 / 1. Auto-picked up by the flow_bench CONFIGURE_DEPENDS glob; run with: bin/flow_bench --benchmark_filter=memtracker Replace the placeholder "< 5% delta" targets in the design doc's Microbenchmarks section with the measured numbers and a projected per-second overhead at an assumed 100K alloc/sec. Headline: ~1.9 ns/pair disabled, ~5.6 ns/pair at the production 1% rate (~0.056% of a core at 100K/s, ~1/17th of R0's 1% ceiling); the every-allocation rows are labeled a buggified worst case, not a default. Testing: built flow_bench on the dev pod (clean, -Werror) and ran the memtracker filter six times; results stable to within a few percent across runs. * design/memory-tracker: describe the coverage test as implemented, not proposed The "Coverage spot-check via sentinel functions" section described the already-implemented `coverage` test in proposal tense ("Add an introspection API:", "The unit test:"), which read as future work. Reword to present tense referencing the actual `coverage`/`*Accounting` tests and the existing `memTrackerForEachSite` API. No remaining references to unwritten test cases. * remove extraneous detail from requirements section * substantially revise microbenchmark results based on seeing 2M allocations/frees on a CPU-maxed storage server * add script to drive A/B experiment for sampled memory allocation tracking * flow/MemoryTracker: move global operator new/delete into a server-only TU The global operator new/delete replacements that route allocations through the memory tracker lived in flow/MemoryTracker.cpp, i.e. in the flow static library. flow is linked into libfdb_c and every client binding, so the interposition shipped into client artifacts and could interpose the whole host process's allocator even with sampling off. Move them into a new fdbserver/GlobalNewDelete.cpp, compiled directly into the fdbserver executable (which clients never link), mirroring where the legacy ALLOC_INSTRUMENTATION overrides already lived. This also makes the replaceable-symbol interposition reliable (guaranteed in the final link) rather than dependent on static-archive pull-in. The legacy ALLOC_INSTRUMENTATION overrides move into the same file, selected by #if defined(ALLOC_INSTRUMENTATION) / #else, so exactly one set of global operators is ever defined. No CMake change is needed (fdbserver/*.cpp is globbed). Also reconcile the design doc with the code: override placement, the Files section (drop the unnecessary flow/CMakeLists.txt edit), the sim knob-table values (REPORT_BYTES_THRESHOLD, SAMPLE_INVERSE prod default), the FORCE_SAMPLE_BYTES "-1 disables" sentinel wording, and drop the stale "buggify inverse to 1" note -- the every-allocation and sampled/weighted paths are already pinned deterministically by MemoryTrackerTest.cpp. Testing: build green (run-ccmk5); fdbserver -r unittests -f /flow/MemoryTracker/ runs all 10 memory-tracker unit tests, 0 failed. * contrib/mako_ab_memtracker: disable RocksDB direct I/O for tmpfs runs RocksDB opens its DB with O_DIRECT by default; /mnt/ram (tmpfs), where the harness puts its data dir, does not support direct I/O, so the storage engine fails to Open and the cluster never configures (fdbcli "configure new" hangs, mako never starts). Pass the existing ROCKSDB_USE_DIRECT_READS / ROCKSDB_USE_DIRECT_IO_FLUSH_COMPACTION knobs (=0) for the rocksdb arm only -- no new knobs added. redwood is unaffected. * fdbserver/bench: move memory-tracker microbench to fdbserver_bench The global operator new/delete override lives in fdbserver/GlobalNewDelete.cpp (server-only, for client isolation), so flow_bench -- which links only flow -- could not exercise it: bench_memtracker_operator_new hit libc++'s operator new and its Arg(100)/Arg(1) rows were identical to Arg(0). Move BenchMemoryTracker.cpp to a new fdbserver/bench/ whose CMake compiles GlobalNewDelete.cpp into the fdbserver_bench executable (via ADDL_SRCS), so the real override is a strong definition in the bench link and the operator-new benchmark measures the actual hooked path. It links only flow, not the fdbserver dependency graph. Adds a BenchMain.cpp (BENCHMARK_MAIN equivalent) and wires the subdirectory into fdbserver/CMakeLists.txt. Testing: fdbserver_bench builds; bench_memtracker_operator_new now shows distinct off / 1% / every-alloc costs (11.4 / 14.4 / 80.9 ns), confirming the override fires. * design/memory-tracker: reconcile with code and slim down Reconcile the doc with the implementation and trim implementation detail that duplicated the code and had begun to drift: - Fix drift found in review: degraded-mode live/peak fields stay 0 (not "tracking the cumulatives"); the dump thresholds on the estimated fields (fix the memTrackerDump header comment too); the live-block table is allocated but empty when live-tracking is off (not "never allocated"); list the test file and its forceLinkMemoryTrackerTests() wiring. - Slim ~220 lines: replace the CallSite struct, the full captureStackFP source, both TraceEvent .detail() schemas, and the file-by-file inventory with prose that defers exact structs/keys/constants to the code; soften the knob table to intent (authoritative defaults live in Knobs.cpp). - Refresh the microbench numbers from fdbserver_bench and annotate the host (AMD EPYC 9R14, clang -O3); replace the A/B placeholder with the measured -16.5% (redwood) / -9.9% (rocksdb); note it is a point-in-time snapshot. - Frame R0 as the target the v1 single-lock design does not yet meet (ships off pending lock sharding); add a one-line note on table teardown/fork behavior. * fix clang-tidy error * mako wrapper scripts: take care to clobber the ramdisk before runs to avoid low-space throttling * design/memory-tracker: note the two mako A/B harnesses and the off-state result Point at contrib/mako_ab_memtracker.py (sampling off vs on) and contrib/mako_ab_binaries.py (vanilla main vs this PR built with tracking off), and record the latter's measured off-state overhead of -0.53% (redwood) / -0.10% (rocksdb) on a shared base commit — well within R0's 1% ceiling. * Add the default code review guidance to AGENTS.md * address big brother review comments; add some braces and trim some generated comments (hard to believe, but true) * clang-tidy again * Final read-through of this PR. -- Add or enhance a few comments on important items (performance & reliability) -- Delete some misc agent-written comments, typically exhibiting recency bias e.g. naming bugs identified in code review passes or describing mundane earlier bugs -- Add braces (InsertBraces style) * memory-tracker: address round-4 review Correctness/robustness: - operator new now runs the installed std::new_handler retry loop, so an allocation failure (including the tracker's own map growth) reaches FDB's platform::outOfMemory / FDB_EXIT_NO_MEM path instead of throwing past it. - Reentrancy guard restored via MemTrackerSuppress RAII on every path (hot path, dump, reset) so an exception can't permanently disable tracking on a thread. - Sampling reseed draws from [1, 2N-1] (mean exactly N); the old [1, 2N] biased the Est* estimate low by ~0.5/N. Design: - Drop runtime enable/disable (now an explicit Non-requirement): the sample knob is read at startup only; park the counter when off. Removes the DISABLED_RESEED re-park and the on/off reconciliation logic. - Simulation samples 1-in-10 (was 1-in-2). Portability (Windows is not build-tested here; lean on existing abstractions): - Aligned operator new uses platform::aligned_alloc/aligned_free (overflow-guarded) instead of posix_memalign; guard <pthread.h> under __linux__; add a force_noinline macro (GNU-only, empty elsewhere); portable volatile-sink escape() in the test. Tooling/tests/docs: - mako A/B scripts: validate the scratch mount (realpath + tmpfs + denylist) before rm -rf, locate mako_storage_bench.sh via __file__, and black-format. - Add operatorNewHonorsNewHandler and samplingRate tests; drop enableAfterOff. - Reconcile the design doc with the code; prune low-value comments. Testing: - /flow/MemoryTracker/* unit tests: 11 pass, 0 fail (bin/fdbserver -r unittests). - Joshua 100k (correctness-8.0.0): 99,995 pass / 1 fail. The single failure is NativeCdcAssignmentPublication -- a NativeCdc test from main, not this PR (CommitProxy failed_to_progress -> QuietDatabase DataDistributionActive -> NativeCdcEndToEnd workload start timed_out). It reproduces bit-identically (seed 2939264355, unseed 8776) with the tracker built off (sim sample_inverse=0, confirmed via the MemoryTrackerSummary SampleInverse trace field), so it is a pre-existing rare CDC/QuietDatabase flake unrelated to this change. * memory-tracker: fix GCC IPA-clone breaking frame-attribution tests Under GCC -O3, IPA constant-propagation cloning (-fipa-cp-clone) specializes the MemoryTrackerTest sentinels (each called with a constant N) into `.constprop` clones emitted at a different address than the function symbol. The executed code -- and thus the captured return addresses -- live in the clone, so the tests' frameInside(frame, &sentinel) window missed them: fastAlloc32Accounting aborted (sitesWithSentinelFrames == 0) in GCC CI while clang passed. Add `noclone` to force_noinline on GCC so each sentinel stays a single body at the address &fn yields. clang doesn't support noclone (and doesn't clone this way), so it keeps noinline only; other compilers stay empty. Testing: /flow/MemoryTracker/* passes 11/11 under both a gcc-toolset-13 build and a clang build. * memory-tracker: cheaper disabled alloc hot path (per-thread off flag) When sampling is off, memTrackerOnAlloc previously still did three TLS accesses every allocation -- a gInMemTracker load, a gMemTrackerCounter load-decrement- STORE, and a gForceSampleBytes load. Add a per-thread gMemTrackerOff flag, checked first, that a thread sets once its slow path observes sampling is off; the disabled alloc path then short-circuits on a single TLS load + branch (no counter store, no gForceSampleBytes load). The flag is per-thread, not global, on purpose: the counter still bootstraps sampling per thread (first alloc reaches the slow path and reads the knob), so a single global gate set by an early main-thread allocation before FLOW_KNOBS is ready would wrongly disable worker threads that bootstrap later. Free keeps the global g_memTrackerEnabled gate (a free-only thread must see global state to debit). memTrackerResetForTest clears the flag. Removes the now-dead INT_MAX counter parking. The saving is real but small (~2 loads + 1 store per alloc, well under the mako A/B's run-to-run noise), so the redwood off-state A/B shows no resolvable change; the win is on principle / at high allocation rates. Testing: /flow/MemoryTracker/* passes 11/11 (bin/fdbserver -r unittests). * memory-tracker: add FDB_MEMORY_TRACKER compile-time gate + per-path microbench Add a compile-time switch, FDB_MEMORY_TRACKER (CMake option, default ON), that removes the feature entirely when set to 0: the header hooks become no-op inlines, flow/MemoryTracker.cpp and the MemoryTrackerTest TEST_CASEs are #if'd out (the forceLink stub stays), and fdbserver/GlobalNewDelete.cpp defines no global operator new/delete override (libc++'s allocator is used, which still honors the installed new_handler). This gives operators an escape hatch to zero always-compiled footprint, and lets the microbench measure present-but-disabled vs absent cost per allocation path. Extend fdbserver/bench/BenchMemoryTracker.cpp with plain per-path alloc/free loops (operator new[] at several sizes, FastAllocator<64/96/256>, Arena medium/huge) so the same binary built =1 (tracker present, sampling off by default) vs =0 (absent) isolates each path's unweighted off-state overhead. Measured (EPYC 9R14 @ 3.7 GHz, ns/op, =1 minus =0): operator new[] small ~+1.1 ns (~11%); huge ~+2.5 ns FastAllocator<N> ~0 (within the ~0.6 ns cross-build noise floor) Arena block ~+3.3 ns (medium) / +4.8 ns (huge) The per-op-costly paths (operator new, Arena) are the low-volume ones; the high-volume path (FastAllocator, ~82% of redwood allocs) is ~free, so the weighted off-state overhead is ~0.1-0.2% of a core -- under the R0 target, though R0 is now framed as an unproven target with this gate as the escape hatch. Testing: /flow/MemoryTracker/* passes 11/11 (default build); FDB_MEMORY_TRACKER=OFF builds clean under -Werror. * clang-tidy fix * comment about why fdbserver/bench exists * address Codex round 5 review comments (MSVC build, startup sequencing, memory allocation failures on tracker-internal bookkeeping, cross-compile, contrib script cleanup) * add another disclaimer about MSVC/Windows being best effort * memory-tracker: fail-open ordering + deflake huge-arena unit test memTrackerSampleAlloc now performs both table insertions (aggregation-map and live-map nodes) before mutating any per-site or global counter, so if the tracker's own map growth throws std::bad_alloc the exception unwinds with all totals in lockstep and the fail-open catch simply drops the sample. This addresses an adversarial-review finding. Note such a failure does not occur in practice: FDB "OOM" is an RSS threshold enforced by fdbmonitor (typically ~12-16 GB against an ~8 GB target), not a malloc/operator-new failure. This feature is for finding leaks and untuned allocations that drive RSS growth, well short of any allocation failure -- documented in flow/MemoryTracker.cpp and design/memory-tracker.md so reviewers don't over-index on the bad_alloc path. arenaHugeAccounting now identifies the huge blocks by their ~100 KB size signature instead of the frame-pointer sentinel. The huge-Arena path is the deepest tracked call chain; under a real (non-simulation) network the best-effort frame-pointer walker is per-allocation nondeterministic there and cannot reliably attribute the blocks to the test's frame, so the sentinel-frame assertion flaked (~1-4% of runs). The recorded block size is correct regardless of which frames were captured, no incidental or foreign-thread allocation comes near 100 KB, and double-tracking still shows up as 2N. The shallower fastAlloc32/arenaSmall/arenaMedium/operatorNew accounting tests keep exact sentinel-frame attribution (reliable on their shorter paths) as the regression guard. Testing: - /flow/MemoryTracker/* via `fdbserver -r unittests`: 500 runs across two seed spaces (including the sequence that previously flaked), 14/14 test cases pass every run, 0 failures. - Builds clean with FDB_MEMORY_TRACKER on and off under -Werror; clang-format and clang-tidy clean on the changed files. - Joshua 100k on the parent commit: ensemble 20260728-160205-gglass-0b30fa74f2605807, ended=100000 pass=100000 fail=0. These changes are a pure counter-update reorder (no simulation-reachable behavior change -- bad_alloc is not injected in sim), a unit-test-only change, and documentation, so that result remains representative. * memory-tracker: note why the fdbserver-local bench binary exists Add a short comment to BenchMain.cpp explaining that most microbenchmarks belong in flow/bench and this fdbserver-local benchmark binary exists only for benchmarks that must link fdbserver-only code, pointing at BenchMemoryTracker.cpp for the detailed rationale rather than duplicating it.
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#include "flow/Knobs.h"
#include "flow/MemoryTracker.h"
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#if defined(ALLOC_INSTRUMENTATION) && defined(__linux__)
#include <cxxabi.h>
#endif
#ifdef ADDRESS_SANITIZER
#include <sanitizer/asan_interface.h>
#endif
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SystemMonitorMachineState machineState;
void initializeSystemMonitorMachineState(SystemMonitorMachineState machineState) {
::machineState = machineState;
ASSERT(g_network);
::machineState.monitorStartTime = now();
}
double machineStartTime() {
return ::machineState.monitorStartTime;
}
void NetworkData::init() {
bytesSent = Int64Metric::getValueOrDefault("Net2.BytesSent"_sr);
countPacketsReceived = Int64Metric::getValueOrDefault("Net2.CountPacketsReceived"_sr);
countPacketsGenerated = Int64Metric::getValueOrDefault("Net2.CountPacketsGenerated"_sr);
bytesReceived = Int64Metric::getValueOrDefault("Net2.BytesReceived"_sr);
countWriteProbes = Int64Metric::getValueOrDefault("Net2.CountWriteProbes"_sr);
countReadProbes = Int64Metric::getValueOrDefault("Net2.CountReadProbes"_sr);
countReads = Int64Metric::getValueOrDefault("Net2.CountReads"_sr);
countWouldBlock = Int64Metric::getValueOrDefault("Net2.CountWouldBlock"_sr);
countWrites = Int64Metric::getValueOrDefault("Net2.CountWrites"_sr);
countRunLoop = Int64Metric::getValueOrDefault("Net2.CountRunLoop"_sr);
countCantSleep = Int64Metric::getValueOrDefault("Net2.CountCantSleep"_sr);
countWontSleep = Int64Metric::getValueOrDefault("Net2.CountWontSleep"_sr);
countTimers = Int64Metric::getValueOrDefault("Net2.CountTimers"_sr);
countTasks = Int64Metric::getValueOrDefault("Net2.CountTasks"_sr);
countYields = Int64Metric::getValueOrDefault("Net2.CountYields"_sr);
countYieldBigStack = Int64Metric::getValueOrDefault("Net2.CountYieldBigStack"_sr);
countYieldCalls = Int64Metric::getValueOrDefault("Net2.CountYieldCalls"_sr);
countASIOEvents = Int64Metric::getValueOrDefault("Net2.CountASIOEvents"_sr);
countYieldCallsTrue = Int64Metric::getValueOrDefault("Net2.CountYieldCallsTrue"_sr);
countRunLoopProfilingSignals = Int64Metric::getValueOrDefault("Net2.CountRunLoopProfilingSignals"_sr);
countConnEstablished = Int64Metric::getValueOrDefault("Net2.CountConnEstablished"_sr);
countConnClosedWithError = Int64Metric::getValueOrDefault("Net2.CountConnClosedWithError"_sr);
countConnClosedWithoutError = Int64Metric::getValueOrDefault("Net2.CountConnClosedWithoutError"_sr);
countTLSPolicyFailures = Int64Metric::getValueOrDefault("Net2.CountTLSPolicyFailures"_sr);
countLaunchTime = DoubleMetric::getValueOrDefault("Net2.CountLaunchTime"_sr);
countReactTime = DoubleMetric::getValueOrDefault("Net2.CountReactTime"_sr);
countFileLogicalWrites = Int64Metric::getValueOrDefault("AsyncFile.CountLogicalWrites"_sr);
countFileLogicalReads = Int64Metric::getValueOrDefault("AsyncFile.CountLogicalReads"_sr);
countAIOSubmit = Int64Metric::getValueOrDefault("AsyncFile.CountAIOSubmit"_sr);
countAIOCollect = Int64Metric::getValueOrDefault("AsyncFile.CountAIOCollect"_sr);
countFileCacheWrites = Int64Metric::getValueOrDefault("AsyncFile.CountCacheWrites"_sr);
countFileCacheReads = Int64Metric::getValueOrDefault("AsyncFile.CountCacheReads"_sr);
countFileCacheWritesBlocked = Int64Metric::getValueOrDefault("AsyncFile.CountCacheWritesBlocked"_sr);
countFileCacheReadsBlocked = Int64Metric::getValueOrDefault("AsyncFile.CountCacheReadsBlocked"_sr);
countFileCachePageReadsMerged = Int64Metric::getValueOrDefault("AsyncFile.CountCachePageReadsMerged"_sr);
countFileCacheFinds = Int64Metric::getValueOrDefault("AsyncFile.CountCacheFinds"_sr);
countFileCacheReadBytes = Int64Metric::getValueOrDefault("AsyncFile.CountCacheReadBytes"_sr);
countFilePageCacheHits = Int64Metric::getValueOrDefault("AsyncFile.CountCachePageReadsHit"_sr);
countFilePageCacheMisses = Int64Metric::getValueOrDefault("AsyncFile.CountCachePageReadsMissed"_sr);
countFilePageCacheEvictions = Int64Metric::getValueOrDefault("EvictablePageCache.CacheEvictions"_sr);
}
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void systemMonitor() {
static StatisticsState statState = StatisticsState();
#if !DEBUG_DETERMINISM
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customSystemMonitor("ProcessMetrics", &statState, true);
#endif
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}
SystemStatistics getSystemStatistics() {
static StatisticsState statState = StatisticsState();
const IPAddress ipAddr = machineState.ip.present() ? machineState.ip.get() : IPAddress();
return getSystemStatistics(
machineState.folder.present() ? machineState.folder.get() : "", &ipAddr, &statState.systemState, false);
}
#define TRACEALLOCATOR(size) \
TraceEvent("MemSample") \
.detail("Count", FastAllocator<size>::getApproximateMemoryUnused() / size) \
.detail("TotalSize", FastAllocator<size>::getApproximateMemoryUnused()) \
.detail("SampleCount", 1) \
.detail("Hash", "FastAllocatedUnused" #size) \
.detail("Bt", "na")
#define DETAILALLOCATORMEMUSAGE(size) \
detail("TotalMemory" #size, FastAllocator<size>::getTotalMemory()) \
.detail("ApproximateUnusedMemory" #size, FastAllocator<size>::getApproximateMemoryUnused()) \
.detail("ActiveThreads" #size, FastAllocator<size>::getActiveThreads())
namespace {
#ifdef __linux__
// Converts cgroup key, e.g. nr_periods, to NrPeriods
std::string capitalizeCgroupKey(const std::string& key) {
bool wordStart = true;
std::string result;
result.reserve(key.size());
for (const char ch : key) {
if (std::isalnum(ch)) {
if (wordStart) {
result.push_back(std::toupper(ch));
wordStart = false;
} else {
result.push_back(ch);
}
} else {
// Skip non-alnum characters
wordStart = true;
}
}
return result;
}
#endif // __linux__
} // anonymous namespace
SystemStatistics customSystemMonitor(std::string const& eventName, StatisticsState* statState, bool machineMetrics) {
const IPAddress ipAddr = machineState.ip.present() ? machineState.ip.get() : IPAddress();
SystemStatistics currentStats = getSystemStatistics(
machineState.folder.present() ? machineState.folder.get() : "", &ipAddr, &statState->systemState, true);
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NetworkData netData;
netData.init();
if (!g_network->isSimulated() && currentStats.initialized) {
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{
TraceEvent(eventName.c_str())
.detail("Elapsed", currentStats.elapsed)
.detail("CPUSeconds", currentStats.processCPUSeconds)
.detail("MainThreadCPUSeconds", currentStats.mainThreadCPUSeconds)
.detail("UptimeSeconds", now() - machineState.monitorStartTime)
.detail("Memory", currentStats.processMemory)
.detail("ResidentMemory", currentStats.processResidentMemory)
.detail("UnusedAllocatedMemory", getTotalUnusedAllocatedMemory())
.detail("MbpsSent",
((netData.bytesSent - statState->networkState.bytesSent) * 8e-6) / currentStats.elapsed)
.detail("MbpsReceived",
((netData.bytesReceived - statState->networkState.bytesReceived) * 8e-6) / currentStats.elapsed)
.detail("DiskTotalBytes", currentStats.processDiskTotalBytes)
.detail("DiskFreeBytes", currentStats.processDiskFreeBytes)
.detail("DiskQueueDepth", currentStats.processDiskQueueDepth)
.detail("DiskIdleSeconds", currentStats.processDiskIdleSeconds)
.detail("DiskReads", currentStats.processDiskRead)
.detail("DiskReadSeconds", currentStats.processDiskReadSeconds)
.detail("DiskWrites", currentStats.processDiskWrite)
.detail("DiskWriteSeconds", currentStats.processDiskWriteSeconds)
.detail("DiskReadsCount", currentStats.processDiskReadCount)
.detail("DiskWritesCount", currentStats.processDiskWriteCount)
.detail("DiskReadSectors", currentStats.processDiskReadSectors)
.detail("DiskWriteSectors", currentStats.processDiskWriteSectors)
.detail("DiskReadBytes", currentStats.processDiskReadBytes)
.detail("DiskWriteBytes", currentStats.processDiskWriteBytes)
.detail("FileWrites", netData.countFileLogicalWrites - statState->networkState.countFileLogicalWrites)
.detail("FileReads", netData.countFileLogicalReads - statState->networkState.countFileLogicalReads)
.detail("CacheReadBytes",
netData.countFileCacheReadBytes - statState->networkState.countFileCacheReadBytes)
.detail("CacheFinds", netData.countFileCacheFinds - statState->networkState.countFileCacheFinds)
.detail("CacheWritesBlocked",
netData.countFileCacheWritesBlocked - statState->networkState.countFileCacheWritesBlocked)
.detail("CacheReadsBlocked",
netData.countFileCacheReadsBlocked - statState->networkState.countFileCacheReadsBlocked)
.detail("CachePageReadsMerged",
netData.countFileCachePageReadsMerged - statState->networkState.countFileCachePageReadsMerged)
.detail("CacheWrites", netData.countFileCacheWrites - statState->networkState.countFileCacheWrites)
.detail("CacheReads", netData.countFileCacheReads - statState->networkState.countFileCacheReads)
.detail("CacheHits", netData.countFilePageCacheHits - statState->networkState.countFilePageCacheHits)
.detail("CacheMisses",
netData.countFilePageCacheMisses - statState->networkState.countFilePageCacheMisses)
.detail("CacheEvictions",
netData.countFilePageCacheEvictions - statState->networkState.countFilePageCacheEvictions)
.detail("DCID", machineState.dcId)
.detail("ZoneID", machineState.zoneId)
.detail("MachineID", machineState.machineId)
.detail("Version", machineState.fdbVersion)
.detail("AIOSubmitCount", netData.countAIOSubmit - statState->networkState.countAIOSubmit)
.detail("AIOCollectCount", netData.countAIOCollect - statState->networkState.countAIOCollect)
.detail("AIOSubmitLag",
(g_network->networkInfo.metrics.secSquaredSubmit -
statState->networkMetricsState.secSquaredSubmit) /
currentStats.elapsed)
.detail("AIODiskStall",
(g_network->networkInfo.metrics.secSquaredDiskStall -
statState->networkMetricsState.secSquaredDiskStall) /
currentStats.elapsed)
.detail("CurrentConnections",
netData.countConnEstablished - netData.countConnClosedWithError -
netData.countConnClosedWithoutError)
.detail("ConnectionsEstablished",
(double)(netData.countConnEstablished - statState->networkState.countConnEstablished) /
currentStats.elapsed)
.detail("ConnectionsClosed",
((netData.countConnClosedWithError - statState->networkState.countConnClosedWithError) +
(netData.countConnClosedWithoutError - statState->networkState.countConnClosedWithoutError)) /
currentStats.elapsed)
.detail("ConnectionErrors",
(netData.countConnClosedWithError - statState->networkState.countConnClosedWithError) /
currentStats.elapsed)
.detail("TLSPolicyFailures",
(netData.countTLSPolicyFailures - statState->networkState.countTLSPolicyFailures) /
currentStats.elapsed)
.trackLatest(eventName);
TraceEvent("MemoryMetrics")
.DETAILALLOCATORMEMUSAGE(16)
.DETAILALLOCATORMEMUSAGE(32)
.DETAILALLOCATORMEMUSAGE(64)
.DETAILALLOCATORMEMUSAGE(96)
.DETAILALLOCATORMEMUSAGE(128)
.DETAILALLOCATORMEMUSAGE(256)
.DETAILALLOCATORMEMUSAGE(512)
.DETAILALLOCATORMEMUSAGE(1024)
.DETAILALLOCATORMEMUSAGE(2048)
.DETAILALLOCATORMEMUSAGE(4096)
.DETAILALLOCATORMEMUSAGE(8192)
.DETAILALLOCATORMEMUSAGE(16384)
.detail("HugeArenaMemory", g_hugeArenaMemory.load())
.detail("DCID", machineState.dcId)
.detail("ZoneID", machineState.zoneId)
.detail("MachineID", machineState.machineId);
uint64_t total_memory = 0;
total_memory += FastAllocator<16>::getTotalMemory();
total_memory += FastAllocator<32>::getTotalMemory();
total_memory += FastAllocator<64>::getTotalMemory();
total_memory += FastAllocator<96>::getTotalMemory();
total_memory += FastAllocator<128>::getTotalMemory();
total_memory += FastAllocator<256>::getTotalMemory();
total_memory += FastAllocator<512>::getTotalMemory();
total_memory += FastAllocator<1024>::getTotalMemory();
total_memory += FastAllocator<2048>::getTotalMemory();
total_memory += FastAllocator<4096>::getTotalMemory();
total_memory += FastAllocator<8192>::getTotalMemory();
total_memory += FastAllocator<16384>::getTotalMemory();
uint64_t unused_memory = 0;
unused_memory += FastAllocator<16>::getApproximateMemoryUnused();
unused_memory += FastAllocator<32>::getApproximateMemoryUnused();
unused_memory += FastAllocator<64>::getApproximateMemoryUnused();
unused_memory += FastAllocator<96>::getApproximateMemoryUnused();
unused_memory += FastAllocator<128>::getApproximateMemoryUnused();
unused_memory += FastAllocator<256>::getApproximateMemoryUnused();
unused_memory += FastAllocator<512>::getApproximateMemoryUnused();
unused_memory += FastAllocator<1024>::getApproximateMemoryUnused();
unused_memory += FastAllocator<2048>::getApproximateMemoryUnused();
unused_memory += FastAllocator<4096>::getApproximateMemoryUnused();
unused_memory += FastAllocator<8192>::getApproximateMemoryUnused();
unused_memory += FastAllocator<16384>::getApproximateMemoryUnused();
if (total_memory > 0) {
TraceEvent("FastAllocMemoryUsage")
.detail("TotalMemory", total_memory)
.detail("UnusedMemory", unused_memory)
.detail("Utilization", format("%f%%", (total_memory - unused_memory) * 100.0 / total_memory));
}
TraceEvent n("NetworkMetrics");
n.detail("Elapsed", currentStats.elapsed)
.detail("CantSleep", netData.countCantSleep - statState->networkState.countCantSleep)
.detail("WontSleep", netData.countWontSleep - statState->networkState.countWontSleep)
.detail("Yields", netData.countYields - statState->networkState.countYields)
.detail("YieldCalls", netData.countYieldCalls - statState->networkState.countYieldCalls)
.detail("YieldCallsTrue", netData.countYieldCallsTrue - statState->networkState.countYieldCallsTrue)
.detail("RunLoopProfilingSignals",
netData.countRunLoopProfilingSignals - statState->networkState.countRunLoopProfilingSignals)
.detail("YieldBigStack", netData.countYieldBigStack - statState->networkState.countYieldBigStack)
.detail("RunLoopIterations", netData.countRunLoop - statState->networkState.countRunLoop)
.detail("TimersExecuted", netData.countTimers - statState->networkState.countTimers)
.detail("TasksExecuted", netData.countTasks - statState->networkState.countTasks)
.detail("ASIOEventsProcessed", netData.countASIOEvents - statState->networkState.countASIOEvents)
.detail("ReadCalls", netData.countReads - statState->networkState.countReads)
.detail("WriteCalls", netData.countWrites - statState->networkState.countWrites)
.detail("ReadProbes", netData.countReadProbes - statState->networkState.countReadProbes)
.detail("WriteProbes", netData.countWriteProbes - statState->networkState.countWriteProbes)
.detail("PacketsRead", netData.countPacketsReceived - statState->networkState.countPacketsReceived)
.detail("PacketsGenerated",
netData.countPacketsGenerated - statState->networkState.countPacketsGenerated)
.detail("WouldBlock", netData.countWouldBlock - statState->networkState.countWouldBlock)
.detail("LaunchTime", netData.countLaunchTime - statState->networkState.countLaunchTime)
.detail("ReactTime", netData.countReactTime - statState->networkState.countReactTime)
.detail("DCID", machineState.dcId)
.detail("ZoneID", machineState.zoneId)
.detail("MachineID", machineState.machineId);
for (int i = 0; i < NetworkMetrics::SLOW_EVENT_BINS; i++) {
if (int c = g_network->networkInfo.metrics.countSlowEvents[i] -
statState->networkMetricsState.countSlowEvents[i]) {
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n.detail(format("SlowTask%dM", 1 << i).c_str(), c);
}
}
std::map<TaskPriority, double> loggedDurations;
for (auto& itr : g_network->networkInfo.metrics.activeTrackers) {
if (itr.second.active) {
itr.second.duration += now() - itr.second.windowedTimer;
itr.second.windowedTimer = now();
}
if (itr.second.duration / currentStats.elapsed >= FLOW_KNOBS->MIN_LOGGED_PRIORITY_BUSY_FRACTION) {
loggedDurations[itr.first] = std::min(currentStats.elapsed, itr.second.duration);
}
itr.second.duration = 0;
}
for (auto const& itr : loggedDurations) {
// PriorityBusyX measures the amount of time spent busy at exactly priority X
n.detail(format("PriorityBusy%d", itr.first).c_str(), itr.second);
}
bool firstTracker = true;
for (auto& itr : g_network->networkInfo.metrics.starvationTrackers) {
if (itr.active) {
itr.duration += now() - itr.windowedTimer;
itr.maxDuration = std::max(itr.maxDuration, now() - itr.timer);
itr.windowedTimer = now();
}
// PriorityStarvedBelowX: how much of the elapsed time we were running tasks at a priority at or above X
// PriorityMaxStarvedBelowX: The longest single span of time that you were starved below that priority,
// which could tell you if you are doing work in bursts.
n.detail(format("PriorityStarvedBelow%d", itr.priority).c_str(),
std::min(currentStats.elapsed, itr.duration));
n.detail(format("PriorityMaxStarvedBelow%d", itr.priority).c_str(), itr.maxDuration);
if (firstTracker) {
g_network->networkInfo.metrics.lastRunLoopBusyness =
std::min(currentStats.elapsed, itr.duration) / currentStats.elapsed;
firstTracker = false;
}
itr.duration = 0;
itr.maxDuration = 0;
}
n.trackLatest("NetworkMetrics");
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}
if (machineMetrics) {
auto traceEvent = TraceEvent("MachineMetrics");
traceEvent.detail("Elapsed", currentStats.elapsed)
.detail("MbpsSent", currentStats.machineMegabitsSent / currentStats.elapsed)
.detail("MbpsReceived", currentStats.machineMegabitsReceived / currentStats.elapsed)
.detail("OutSegs", currentStats.machineOutSegs)
.detail("RetransSegs", currentStats.machineRetransSegs)
.detail("CPUSeconds", currentStats.machineCPUSeconds)
.detail("TotalMemory", currentStats.machineTotalRAM)
.detail("CommittedMemory", currentStats.machineCommittedRAM)
.detail("AvailableMemory", currentStats.machineAvailableRAM)
.detail("DCID", machineState.dcId)
.detail("ZoneID", machineState.zoneId)
.detail("MachineID", machineState.machineId)
.detail("DatahallID", machineState.datahallId)
.trackLatest("MachineMetrics");
#ifdef __linux__
for (const auto& [k, v] : linux_os::reportCGroupCpuStat()) {
traceEvent.detail(capitalizeCgroupKey(k).c_str(), v);
}
#endif // __linux__
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}
}
#ifdef ALLOC_INSTRUMENTATION
{
static double firstTime = 0.0;
if (firstTime == 0.0)
firstTime = now();
if (now() - firstTime > 10 || g_network->isSimulated()) {
firstTime = now();
std::vector<std::pair<std::string, const char*>> typeNames;
for (auto i = allocInstr.begin(); i != allocInstr.end(); ++i) {
std::string s;
#ifdef __linux__
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char* demangled = abi::__cxa_demangle(i->first, nullptr, nullptr, nullptr);
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if (demangled) {
s = demangled;
if (StringRef(s).startsWith("(anonymous namespace)::"_sr))
s = s.substr("(anonymous namespace)::"_sr.size());
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free(demangled);
} else
s = i->first;
#else
s = i->first;
if (StringRef(s).startsWith("class `anonymous namespace'::"_sr))
s = s.substr("class `anonymous namespace'::"_sr.size());
else if (StringRef(s).startsWith("class "_sr))
s = s.substr("class "_sr.size());
else if (StringRef(s).startsWith("struct "_sr))
s = s.substr("struct "_sr.size());
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#endif
typeNames.emplace_back(s, i->first);
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}
std::sort(typeNames.begin(), typeNames.end());
for (int i = 0; i < typeNames.size(); i++) {
const char* n = typeNames[i].second;
auto& f = allocInstr[n];
if (f.maxAllocated > 10000)
TraceEvent("AllocInstrument")
.detail("CurrentAlloc", f.allocCount - f.deallocCount)
.detail("Name", typeNames[i].first.c_str());
}
std::unordered_map<uint32_t, BackTraceAccount> traceCounts;
size_t memSampleSize;
memSample_entered = true;
{
ThreadSpinLockHolder holder(memLock);
traceCounts = backTraceLookup;
memSampleSize = memSample.size();
}
memSample_entered = false;
uint64_t totalSize = 0;
uint64_t totalCount = 0;
for (auto i = traceCounts.begin(); i != traceCounts.end(); ++i) {
std::vector<void*>* frames = i->second.backTrace;
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std::string backTraceStr = platform::format_backtrace(&(*frames)[0], frames->size());
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TraceEvent("MemSample")
.detail("Count", (int64_t)i->second.count)
.detail("TotalSize", i->second.totalSize)
.detail("SampleCount", i->second.sampleCount)
.detail("Hash", format("%lld", i->first))
.detail("Bt", backTraceStr);
totalSize += i->second.totalSize;
totalCount += i->second.count;
}
TraceEvent("MemSampleSummary")
.detail("InverseByteSampleRatio", SAMPLE_BYTES)
.detail("MemorySamples", memSampleSize)
.detail("BackTraces", traceCounts.size())
.detail("TotalSize", totalSize)
.detail("TotalCount", totalCount);
TraceEvent("MemSample")
.detail("Count", traceCounts.size())
.detail("TotalSize", traceCounts.size() * ((int)(sizeof(uint32_t) + sizeof(size_t) + sizeof(size_t))))
.detail("SampleCount", traceCounts.size())
.detail("Hash", "backTraces")
.detail("Bt", "na");
TraceEvent("MemSample")
.detail("Count", memSampleSize)
.detail("TotalSize", memSampleSize * ((int)(sizeof(void*) + sizeof(uint32_t) + sizeof(size_t))))
.detail("SampleCount", memSampleSize)
.detail("Hash", "memSamples")
.detail("Bt", "na");
TRACEALLOCATOR(16);
TRACEALLOCATOR(32);
TRACEALLOCATOR(64);
TRACEALLOCATOR(96);
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TRACEALLOCATOR(128);
TRACEALLOCATOR(256);
TRACEALLOCATOR(512);
TRACEALLOCATOR(1024);
TRACEALLOCATOR(2048);
TRACEALLOCATOR(4096);
TRACEALLOCATOR(8192);
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}
}
#endif
statState->networkMetricsState = g_network->networkInfo.metrics;
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statState->networkState = netData;
call-site aware memory tracking (#13344) * Initial memory tracking design doc draft, plus first round of review comments by me with // TODO annotations * design/memory-tracker: address first-round review TODOs Resolves all // TODO annotations from the initial draft: - live-block table now optional via MEMORY_TRACKING_LIVE_TRACKING knob - drop the mmap slab pool; std::malloc + in-tracker flag is sufficient - add MEMORY_TRACKING_FORCE_SAMPLE_BYTES so large allocations are always captured regardless of the count-rate sampler - add live block / byte totals to MemoryTrackerSummary - replace the manual coverage spot-check with a sentinel-function unit test that introspects the aggregation table directly - leave ALLOC_INSTRUMENTATION alone; new hooks sit next to (not replacing) existing conditional ones - drop SJLJ jargon, trim A4 alternative now that force-sample-large collapses the byte-rate-vs-count-rate question * flow: add sampled per-call-site memory tracker Adds a sampled memory attribution layer (flow/MemoryTracker.{h,cpp}) hooked into the three primary allocation paths — global operator new/delete, FastAllocator, and ArenaBlock::create — plus a periodic TraceEvent dump driven from SystemMonitor. Knobs gate sample rate, force-sample threshold, report cadence, top-N, and capture depth; prod default is off. See design/memory-tracker.md. Test fixes uncovered while bringing the unit tests up: - memTrackerResetForTest now resets the per-thread sample counter and force-sample threshold. Without this, a test that exercised the off-switch path left gMemTrackerCounter at INT_MAX, which then silently suppressed sampling for the remainder of the run. - Slow-path reseed special-cases inverse==1 to keep the counter at 1. The general formula 1 + r % (2*inverse) yields counter values 1 or 2 at inverse==1, sampling only ~67% of allocations rather than every one, which broke a test that asserts exact alloc counts. - Sentinel functions in MemoryTrackerTest.cpp now route the allocated pointer through an asm-volatile escape() helper. Clang -O3 was eliding the new/delete pair (P0593 heap fusion), so the test's allocations never reached the operator-new override. * design/memory-tracker: address second-round review - threshold-based reporting (80 MB default, ~1% of 8 GB target RSS) replaces fixed top-N - prod report interval 60 s -> 10 min; sim stays 30 s - single combined MemoryTrackerAddrCmd event with one addr2line invocation per dump (positional mapping back to sites), keeping frame 0 — old design's per-site format_backtrace dropped the leaf alloc frame - new R12 "Side-thread coverage" + "Side-thread safety" subsection documenting the FP-elision crash mode found via joshua repros (RandomUnitTests / IThreadPool seeds segfaulted in captureStackFP when walking from FastAllocator<N>::~ThreadData into glibc's FP-elided pthread shutdown machinery) and the stack-bounds mitigation via pthread_getattr_np - R7 wording: live bytes (not cumulative) - CallSite struct in design overview aligned with implementation; ForceSampledCount promoted from prose-only to struct + emitted detail; exemplarFrames sized to MEMORY_TRACKER_MAX_FRAMES (=10) matching the FRAMES knob's stated 1-10 range - LIVE_TRACKING=false degraded-mode interaction documented - stale "slab pool" refs removed (std::malloc was already in code) and fdbserver.cpp self-contradiction resolved - R3 / Rollout reconciled (table shows steady-state, step 1 lands at 0) - 4-6 frame count flagged as initial estimate, subject to refinement - file:line citations stripped from path references (line numbers drift; symbol names are stable) * flow: threshold-based memory tracker reporting + side-thread safety Implements the second-round design changes in flow/MemoryTracker.{cpp,h}, flow/Knobs.{cpp,h}, flow/SystemMonitor.cpp. - MEMORY_TRACKING_TOP_N -> MEMORY_TRACKING_REPORT_BYTES_THRESHOLD (int64_t, default 80,000,000). MEMORY_TRACKING_REPORT_INTERVAL prod default 60.0 -> 600.0; sim still 30.0. - memTrackerDump(int topN) -> memTrackerDump(int64_t bytesThreshold). Filters by liveBytes (or cumulativeBytes when LIVE_TRACKING=false) >= threshold; emits MemoryTrackerSite per qualifying site plus one MemoryTrackerAddrCmd event with a single addr2line invocation covering every qualifying site's frames in dump order. The Summary event picks up SitesReported and ReportBytesThreshold details. - AddrCmd is built directly here (not via platform::format_backtrace, which deliberately drops index 0 for its single-site use case); the leaf alloc frame is preserved. - captureFramesFP gains a per-thread stack-bounds check via pthread_getattr_np + pthread_attr_getstack, cached in TLS. Without it, walking the FP chain from FastAllocator<N>::~ThreadData into glibc's FP-elided pthread shutdown machinery follows an uninitialized saved-FP slot and dereferences garbage. Fixes the joshua-found segfaults on RandomUnitTests seeds 3288611985, 3731245491, and 2219741568 (all in the IThreadPool worker-exit path). See design/memory-tracker.md "Side-thread safety". * flow/MemoryTracker: stub the FP walker on non-Linux pthread_getattr_np is glibc-specific and the macOS build broke on it. Frame-pointer walking on macOS is also unreliable on its own (system runtime has -fomit-frame-pointer in places we can't control), so a "loose bounds" workaround would still risk crashes. FDB is required to compile on macOS but is not run in production there. Gate initStackBoundsForThread + the real captureFramesFP on __linux__; provide a return-0 stub on non-Linux. The rest of the tracker (sample counters, aggregation, dump) still compiles and runs; per-call-site reports on macOS will just lack stack attribution. * flow: clang-format fixup for memory-tracker files Whitespace-only. Catches up flow/Arena.cpp and flow/MemoryTrackerTest.cpp with the project's clang-format style; the original implementation commit (d587f82b) slipped these past the format pre-flight. * edit for clarity, brevity, and uniform voice * flow/Arena: fix double-tracking on the >256/huge ArenaBlock paths ArenaBlock::create's >256 and huge paths go through allocateAndMaybeKeepalive (`new uint8_t[]`), which fires the global operator new[] hook in addition to the explicit memTrackerOnAlloc that fires immediately after. Two sites tracked the same pointer; on free only the explicit-Arena fingerprint was debited, so the operator new[] fingerprint accumulated liveBytes monotonically and LiveBytesTotal/LiveBlocksTotal skewed by +n/+1 per arena alloc/free pair. Reported as B1 in the PR review. Fix at the Arena layer (so non-arena allocateAndMaybeKeepalive callers in serialize.h's PacketBuffer code remain attributed at the operator-new layer): a MemTrackerSuppress RAII helper held across the underlying new[]/delete[] in ArenaBlock::create and ArenaBlock::destroyLeaf. Adds accounting tests for FastAllocator<32>, Arena small, Arena medium (the B1 path), and Arena huge. The load-bearing assertion is "exactly one site has the sentinel's frames AND nonzero bytes" -- fails pre-fix for medium/huge with sites=2. Tests gate on __linux__ since captureFramesFP is a no-op on macOS. * flow/memory-tracker: address PR review follow-ups - Knobs.cpp: sim default for MEMORY_TRACKING_REPORT_BYTES_THRESHOLD drops 80 MB -> 1 MB so sim dumps surface more sites for manual sanity-checking. Prod unchanged. - B2: memTrackerForEachSite holds MemTrackerSuppress across the callback loop so callbacks that allocate (e.g. fprintf failure dumps) don't re-enter tracking under SAMPLE_INVERSE=1. - B8: drop the always-zero g_reentrantBailouts and its SamplesDroppedReentry summary detail. Wiring it would require an atomic in the inline hot path, which R1 forbids. Design doc updated. - B3/B6/B7/B9: explanatory comments only -- frame-strip-count inlining assumption (B3), unstable sort acceptable under R6 (B6), shared xorshift seed acceptable in practice (B7), MEMORY_TRACKING_LIVE_TRACKING is startup-only (B9). * flow/MemoryTracker: one addr2line per site, drop chunking Move the addr2line command back onto MemoryTrackerSite as a per-site AddrCmd detail and remove the MemoryTrackerAddrCmd event entirely. Each AddrCmd carries exactly that site's stack -- short, well under the trace-detail truncation cap, ready to paste. Replaces the consolidated-then-chunked-into-byte-buckets approach, which split stacks across chunk boundaries and made raw events hard to read. * add standard Apache 2.0 license headers to new memory-tracker files The three new files (flow/MemoryTracker.{cpp,h} and flow/MemoryTrackerTest.cpp) shipped without the project-standard copyright/license block. Adds the standard 19-line header to each; file-purpose comments stay below it, switched to // line comments to keep the license block visually distinct. AGENTS.md gains a short "Source File Headers" section so the next contributor doesn't repeat the omission. * address review comments; reduce cost of enable check; maintain net estimates so users dont have to do it manually * formatting * unit test bug fix * gglass review comments on memory-tracker.md design doc * design doc updates, and fill in a plan for remaining tests/benchmarks * delete useless simulation section * flow/bench: add memory-tracker microbenchmarks; record measured overhead Add flow/bench/BenchMemoryTracker.cpp (Google Benchmark) measuring the tracker's per-op cost via three benchmarks -- raw malloc/free baseline, end-to-end operator new/delete, and isolated memTrackerOnAlloc/OnFree -- each at sample inverse 0 / 100 / 1. Auto-picked up by the flow_bench CONFIGURE_DEPENDS glob; run with: bin/flow_bench --benchmark_filter=memtracker Replace the placeholder "< 5% delta" targets in the design doc's Microbenchmarks section with the measured numbers and a projected per-second overhead at an assumed 100K alloc/sec. Headline: ~1.9 ns/pair disabled, ~5.6 ns/pair at the production 1% rate (~0.056% of a core at 100K/s, ~1/17th of R0's 1% ceiling); the every-allocation rows are labeled a buggified worst case, not a default. Testing: built flow_bench on the dev pod (clean, -Werror) and ran the memtracker filter six times; results stable to within a few percent across runs. * design/memory-tracker: describe the coverage test as implemented, not proposed The "Coverage spot-check via sentinel functions" section described the already-implemented `coverage` test in proposal tense ("Add an introspection API:", "The unit test:"), which read as future work. Reword to present tense referencing the actual `coverage`/`*Accounting` tests and the existing `memTrackerForEachSite` API. No remaining references to unwritten test cases. * remove extraneous detail from requirements section * substantially revise microbenchmark results based on seeing 2M allocations/frees on a CPU-maxed storage server * add script to drive A/B experiment for sampled memory allocation tracking * flow/MemoryTracker: move global operator new/delete into a server-only TU The global operator new/delete replacements that route allocations through the memory tracker lived in flow/MemoryTracker.cpp, i.e. in the flow static library. flow is linked into libfdb_c and every client binding, so the interposition shipped into client artifacts and could interpose the whole host process's allocator even with sampling off. Move them into a new fdbserver/GlobalNewDelete.cpp, compiled directly into the fdbserver executable (which clients never link), mirroring where the legacy ALLOC_INSTRUMENTATION overrides already lived. This also makes the replaceable-symbol interposition reliable (guaranteed in the final link) rather than dependent on static-archive pull-in. The legacy ALLOC_INSTRUMENTATION overrides move into the same file, selected by #if defined(ALLOC_INSTRUMENTATION) / #else, so exactly one set of global operators is ever defined. No CMake change is needed (fdbserver/*.cpp is globbed). Also reconcile the design doc with the code: override placement, the Files section (drop the unnecessary flow/CMakeLists.txt edit), the sim knob-table values (REPORT_BYTES_THRESHOLD, SAMPLE_INVERSE prod default), the FORCE_SAMPLE_BYTES "-1 disables" sentinel wording, and drop the stale "buggify inverse to 1" note -- the every-allocation and sampled/weighted paths are already pinned deterministically by MemoryTrackerTest.cpp. Testing: build green (run-ccmk5); fdbserver -r unittests -f /flow/MemoryTracker/ runs all 10 memory-tracker unit tests, 0 failed. * contrib/mako_ab_memtracker: disable RocksDB direct I/O for tmpfs runs RocksDB opens its DB with O_DIRECT by default; /mnt/ram (tmpfs), where the harness puts its data dir, does not support direct I/O, so the storage engine fails to Open and the cluster never configures (fdbcli "configure new" hangs, mako never starts). Pass the existing ROCKSDB_USE_DIRECT_READS / ROCKSDB_USE_DIRECT_IO_FLUSH_COMPACTION knobs (=0) for the rocksdb arm only -- no new knobs added. redwood is unaffected. * fdbserver/bench: move memory-tracker microbench to fdbserver_bench The global operator new/delete override lives in fdbserver/GlobalNewDelete.cpp (server-only, for client isolation), so flow_bench -- which links only flow -- could not exercise it: bench_memtracker_operator_new hit libc++'s operator new and its Arg(100)/Arg(1) rows were identical to Arg(0). Move BenchMemoryTracker.cpp to a new fdbserver/bench/ whose CMake compiles GlobalNewDelete.cpp into the fdbserver_bench executable (via ADDL_SRCS), so the real override is a strong definition in the bench link and the operator-new benchmark measures the actual hooked path. It links only flow, not the fdbserver dependency graph. Adds a BenchMain.cpp (BENCHMARK_MAIN equivalent) and wires the subdirectory into fdbserver/CMakeLists.txt. Testing: fdbserver_bench builds; bench_memtracker_operator_new now shows distinct off / 1% / every-alloc costs (11.4 / 14.4 / 80.9 ns), confirming the override fires. * design/memory-tracker: reconcile with code and slim down Reconcile the doc with the implementation and trim implementation detail that duplicated the code and had begun to drift: - Fix drift found in review: degraded-mode live/peak fields stay 0 (not "tracking the cumulatives"); the dump thresholds on the estimated fields (fix the memTrackerDump header comment too); the live-block table is allocated but empty when live-tracking is off (not "never allocated"); list the test file and its forceLinkMemoryTrackerTests() wiring. - Slim ~220 lines: replace the CallSite struct, the full captureStackFP source, both TraceEvent .detail() schemas, and the file-by-file inventory with prose that defers exact structs/keys/constants to the code; soften the knob table to intent (authoritative defaults live in Knobs.cpp). - Refresh the microbench numbers from fdbserver_bench and annotate the host (AMD EPYC 9R14, clang -O3); replace the A/B placeholder with the measured -16.5% (redwood) / -9.9% (rocksdb); note it is a point-in-time snapshot. - Frame R0 as the target the v1 single-lock design does not yet meet (ships off pending lock sharding); add a one-line note on table teardown/fork behavior. * fix clang-tidy error * mako wrapper scripts: take care to clobber the ramdisk before runs to avoid low-space throttling * design/memory-tracker: note the two mako A/B harnesses and the off-state result Point at contrib/mako_ab_memtracker.py (sampling off vs on) and contrib/mako_ab_binaries.py (vanilla main vs this PR built with tracking off), and record the latter's measured off-state overhead of -0.53% (redwood) / -0.10% (rocksdb) on a shared base commit — well within R0's 1% ceiling. * Add the default code review guidance to AGENTS.md * address big brother review comments; add some braces and trim some generated comments (hard to believe, but true) * clang-tidy again * Final read-through of this PR. -- Add or enhance a few comments on important items (performance & reliability) -- Delete some misc agent-written comments, typically exhibiting recency bias e.g. naming bugs identified in code review passes or describing mundane earlier bugs -- Add braces (InsertBraces style) * memory-tracker: address round-4 review Correctness/robustness: - operator new now runs the installed std::new_handler retry loop, so an allocation failure (including the tracker's own map growth) reaches FDB's platform::outOfMemory / FDB_EXIT_NO_MEM path instead of throwing past it. - Reentrancy guard restored via MemTrackerSuppress RAII on every path (hot path, dump, reset) so an exception can't permanently disable tracking on a thread. - Sampling reseed draws from [1, 2N-1] (mean exactly N); the old [1, 2N] biased the Est* estimate low by ~0.5/N. Design: - Drop runtime enable/disable (now an explicit Non-requirement): the sample knob is read at startup only; park the counter when off. Removes the DISABLED_RESEED re-park and the on/off reconciliation logic. - Simulation samples 1-in-10 (was 1-in-2). Portability (Windows is not build-tested here; lean on existing abstractions): - Aligned operator new uses platform::aligned_alloc/aligned_free (overflow-guarded) instead of posix_memalign; guard <pthread.h> under __linux__; add a force_noinline macro (GNU-only, empty elsewhere); portable volatile-sink escape() in the test. Tooling/tests/docs: - mako A/B scripts: validate the scratch mount (realpath + tmpfs + denylist) before rm -rf, locate mako_storage_bench.sh via __file__, and black-format. - Add operatorNewHonorsNewHandler and samplingRate tests; drop enableAfterOff. - Reconcile the design doc with the code; prune low-value comments. Testing: - /flow/MemoryTracker/* unit tests: 11 pass, 0 fail (bin/fdbserver -r unittests). - Joshua 100k (correctness-8.0.0): 99,995 pass / 1 fail. The single failure is NativeCdcAssignmentPublication -- a NativeCdc test from main, not this PR (CommitProxy failed_to_progress -> QuietDatabase DataDistributionActive -> NativeCdcEndToEnd workload start timed_out). It reproduces bit-identically (seed 2939264355, unseed 8776) with the tracker built off (sim sample_inverse=0, confirmed via the MemoryTrackerSummary SampleInverse trace field), so it is a pre-existing rare CDC/QuietDatabase flake unrelated to this change. * memory-tracker: fix GCC IPA-clone breaking frame-attribution tests Under GCC -O3, IPA constant-propagation cloning (-fipa-cp-clone) specializes the MemoryTrackerTest sentinels (each called with a constant N) into `.constprop` clones emitted at a different address than the function symbol. The executed code -- and thus the captured return addresses -- live in the clone, so the tests' frameInside(frame, &sentinel) window missed them: fastAlloc32Accounting aborted (sitesWithSentinelFrames == 0) in GCC CI while clang passed. Add `noclone` to force_noinline on GCC so each sentinel stays a single body at the address &fn yields. clang doesn't support noclone (and doesn't clone this way), so it keeps noinline only; other compilers stay empty. Testing: /flow/MemoryTracker/* passes 11/11 under both a gcc-toolset-13 build and a clang build. * memory-tracker: cheaper disabled alloc hot path (per-thread off flag) When sampling is off, memTrackerOnAlloc previously still did three TLS accesses every allocation -- a gInMemTracker load, a gMemTrackerCounter load-decrement- STORE, and a gForceSampleBytes load. Add a per-thread gMemTrackerOff flag, checked first, that a thread sets once its slow path observes sampling is off; the disabled alloc path then short-circuits on a single TLS load + branch (no counter store, no gForceSampleBytes load). The flag is per-thread, not global, on purpose: the counter still bootstraps sampling per thread (first alloc reaches the slow path and reads the knob), so a single global gate set by an early main-thread allocation before FLOW_KNOBS is ready would wrongly disable worker threads that bootstrap later. Free keeps the global g_memTrackerEnabled gate (a free-only thread must see global state to debit). memTrackerResetForTest clears the flag. Removes the now-dead INT_MAX counter parking. The saving is real but small (~2 loads + 1 store per alloc, well under the mako A/B's run-to-run noise), so the redwood off-state A/B shows no resolvable change; the win is on principle / at high allocation rates. Testing: /flow/MemoryTracker/* passes 11/11 (bin/fdbserver -r unittests). * memory-tracker: add FDB_MEMORY_TRACKER compile-time gate + per-path microbench Add a compile-time switch, FDB_MEMORY_TRACKER (CMake option, default ON), that removes the feature entirely when set to 0: the header hooks become no-op inlines, flow/MemoryTracker.cpp and the MemoryTrackerTest TEST_CASEs are #if'd out (the forceLink stub stays), and fdbserver/GlobalNewDelete.cpp defines no global operator new/delete override (libc++'s allocator is used, which still honors the installed new_handler). This gives operators an escape hatch to zero always-compiled footprint, and lets the microbench measure present-but-disabled vs absent cost per allocation path. Extend fdbserver/bench/BenchMemoryTracker.cpp with plain per-path alloc/free loops (operator new[] at several sizes, FastAllocator<64/96/256>, Arena medium/huge) so the same binary built =1 (tracker present, sampling off by default) vs =0 (absent) isolates each path's unweighted off-state overhead. Measured (EPYC 9R14 @ 3.7 GHz, ns/op, =1 minus =0): operator new[] small ~+1.1 ns (~11%); huge ~+2.5 ns FastAllocator<N> ~0 (within the ~0.6 ns cross-build noise floor) Arena block ~+3.3 ns (medium) / +4.8 ns (huge) The per-op-costly paths (operator new, Arena) are the low-volume ones; the high-volume path (FastAllocator, ~82% of redwood allocs) is ~free, so the weighted off-state overhead is ~0.1-0.2% of a core -- under the R0 target, though R0 is now framed as an unproven target with this gate as the escape hatch. Testing: /flow/MemoryTracker/* passes 11/11 (default build); FDB_MEMORY_TRACKER=OFF builds clean under -Werror. * clang-tidy fix * comment about why fdbserver/bench exists * address Codex round 5 review comments (MSVC build, startup sequencing, memory allocation failures on tracker-internal bookkeeping, cross-compile, contrib script cleanup) * add another disclaimer about MSVC/Windows being best effort * memory-tracker: fail-open ordering + deflake huge-arena unit test memTrackerSampleAlloc now performs both table insertions (aggregation-map and live-map nodes) before mutating any per-site or global counter, so if the tracker's own map growth throws std::bad_alloc the exception unwinds with all totals in lockstep and the fail-open catch simply drops the sample. This addresses an adversarial-review finding. Note such a failure does not occur in practice: FDB "OOM" is an RSS threshold enforced by fdbmonitor (typically ~12-16 GB against an ~8 GB target), not a malloc/operator-new failure. This feature is for finding leaks and untuned allocations that drive RSS growth, well short of any allocation failure -- documented in flow/MemoryTracker.cpp and design/memory-tracker.md so reviewers don't over-index on the bad_alloc path. arenaHugeAccounting now identifies the huge blocks by their ~100 KB size signature instead of the frame-pointer sentinel. The huge-Arena path is the deepest tracked call chain; under a real (non-simulation) network the best-effort frame-pointer walker is per-allocation nondeterministic there and cannot reliably attribute the blocks to the test's frame, so the sentinel-frame assertion flaked (~1-4% of runs). The recorded block size is correct regardless of which frames were captured, no incidental or foreign-thread allocation comes near 100 KB, and double-tracking still shows up as 2N. The shallower fastAlloc32/arenaSmall/arenaMedium/operatorNew accounting tests keep exact sentinel-frame attribution (reliable on their shorter paths) as the regression guard. Testing: - /flow/MemoryTracker/* via `fdbserver -r unittests`: 500 runs across two seed spaces (including the sequence that previously flaked), 14/14 test cases pass every run, 0 failures. - Builds clean with FDB_MEMORY_TRACKER on and off under -Werror; clang-format and clang-tidy clean on the changed files. - Joshua 100k on the parent commit: ensemble 20260728-160205-gglass-0b30fa74f2605807, ended=100000 pass=100000 fail=0. These changes are a pure counter-update reorder (no simulation-reachable behavior change -- bad_alloc is not injected in sim), a unit-test-only change, and documentation, so that result remains representative. * memory-tracker: note why the fdbserver-local bench binary exists Add a short comment to BenchMain.cpp explaining that most microbenchmarks belong in flow/bench and this fdbserver-local benchmark binary exists only for benchmarks that must link fdbserver-only code, pointing at BenchMemoryTracker.cpp for the detailed rationale rather than duplicating it.
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// Periodic dump of the per-call-site memory tracker; cadence from the
// MEMORY_TRACKING_REPORT_INTERVAL knob (<=0 disables). In simulation the
// tracker's tables and this static are shared across all simulated
// processes, so one dump fires per interval cluster-wide and its site
// numbers blend every process — correct only in a real single-process server.
if (FLOW_KNOBS && FLOW_KNOBS->MEMORY_TRACKING_REPORT_INTERVAL > 0) {
static double lastMemTrackerDump = 0;
if (now() - lastMemTrackerDump >= FLOW_KNOBS->MEMORY_TRACKING_REPORT_INTERVAL) {
memTrackerDump(FLOW_KNOBS->MEMORY_TRACKING_REPORT_BYTES_THRESHOLD);
lastMemTrackerDump = now();
}
}
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return currentStats;
}
Future<Void> startMemoryUsageMonitor(uint64_t memLimit) {
if (memLimit == 0) {
return Void();
}
auto checkMemoryUsage = [=]() {
if (getResidentMemoryUsage() > memLimit) {
#if defined(ADDRESS_SANITIZER) && defined(__linux__)
__sanitizer_print_memory_profile(/*top percent*/ 100, /*max contexts*/ 10);
#endif
platform::outOfMemory();
}
};
return recurring(checkMemoryUsage, FLOW_KNOBS->MEMORY_USAGE_CHECK_INTERVAL);
}