This patch fixes the "performance regression" reported in https://bugs.llvm.org/show_bug.cgi?id=51235. In fact it has nothing to do with performance. The root cause is, the stolen task is not allowed to execute by another thread because by default it is tied task. Since hidden helper task will always be executed by hidden helper threads, it should be untied.
Reviewed By: protze.joachim
Differential Revision: https://reviews.llvm.org/D107121
When loading libomptarget, the init function in libomptarget/src/rtl.cpp
will search for the libomptarget_start_tool function using libdl.
libomptarget_start_tool will pass those OMPT callbacks related to target
constructs to libomptarget
Differential Revision: https://reviews.llvm.org/D99803
Fix for https://bugs.llvm.org/show_bug.cgi?id=49723.
Eliminated references from task dependency hash to node allocated on stack,
thus eliminated accesses to stale memory. So the node now never freed.
Uncommented assertion which triggered when stale memory accessed.
Removed unneeded ref count increment for stack allocated node.
Differential Revision: https://reviews.llvm.org/D106705
Put declarations/definitions of unused variables under corresponding macros
to silence clang build warnings.
Differential Revision: https://reviews.llvm.org/D106608
Two-level distributed barrier is a new experimental barrier designed
for Intel hardware that has better performance in some cases than the
default hyper barrier.
This barrier is designed to handle fine granularity parallelism where
barriers are used frequently with little compute and memory access
between barriers. There is no need to use it for codes with few
barriers and large granularity compute, or memory intensive
applications, as little difference will be seen between this barrier
and the default hyper barrier. This barrier is designed to work
optimally with a fixed number of threads, and has a significant setup
time, so should NOT be used in situations where the number of threads
in a team is varied frequently.
The two-level distributed barrier is off by default -- hyper barrier
is used by default. To use this barrier, you must set all barrier
patterns to use this type, because it will not work with other barrier
patterns. Thus, to turn it on, the following settings are required:
KMP_FORKJOIN_BARRIER_PATTERN=dist,dist
KMP_PLAIN_BARRIER_PATTERN=dist,dist
KMP_REDUCTION_BARRIER_PATTERN=dist,dist
Branching factors (set with KMP_FORKJOIN_BARRIER, KMP_PLAIN_BARRIER,
and KMP_REDUCTION_BARRIER) are ignored by the two-level distributed
barrier.
Patch fixed for ITTNotify disabled builds and non-x86 builds
Co-authored-by: Jonathan Peyton <jonathan.l.peyton@intel.com>
Co-authored-by: Vladislav Vinogradov <vlad.vinogradov@intel.com>
Differential Revision: https://reviews.llvm.org/D103121
This patch fixes https://bugs.llvm.org/show_bug.cgi?id=49066.
For detachable tasks, the assumption breaks that the proxy task cannot have
remaining child tasks when the proxy completes.
In stead of increment/decrement the incomplete task count, a high-order bit
is flipped to mark and wait for the incomplete proxy task.
Differential Revision: https://reviews.llvm.org/D101082
OMPD is enabled by default on Linux machines and disabled on others.
However, if explicitly enabled it throws an error and exit while configuring.
It is mentioned in Bug: https://bugs.llvm.org/show_bug.cgi?id=51121
This patch, instead of throwing error, disables OMPD support with a warning message,
so configuration can continue.
Reviewed By: @protze.joachim
Differential Revision: https://reviews.llvm.org/D106682
gcc 11 introduced support for depend clause, but the gomp interface of libomp
does not yet handle the information.
Also remove -fopenmp-version=50, which is no longer needed for clang, but not
supported by gcc.
Bug 50022 [0] reports target nowait fails in certain case, which is added in this
patch. The root cause of the failure is, when the second task is created, its
parent's `td_incomplete_child_tasks` will not be incremented because there is no
parallel region here thus its team is serialized. Therefore, when the initial
thread is waiting for its unfinished children tasks, it thought there is only
one, the first task, because it is hidden helper task, so it is tracked. The
second task will only be pushed to the queue when the first task is finished.
However, when the first task finishes, it first decrements the counter of its
parent, and then release dependences. Once the counter is decremented, the thread
will move on because its counter is reset, but actually, the second task has not
been executed at all. As a result, since in this case, the main function finishes,
then `libomp` starts to destroy. When the second task is pushed somewhere, all
some of the structures might already have already been destroyed, then anything
could happen.
This patch simply moves `__kmp_release_deps` ahead of decrement of the counter.
In this way, we can make sure that the initial thread is aware of the existence
of another task(s) so it will not move on. In addition, in order to tackle
dependence chain starting with hidden helper thread, when hidden helper task is
encountered, we force the task to release dependences.
Reference:
[0] https://bugs.llvm.org/show_bug.cgi?id=50022
Reviewed By: AndreyChurbanov
Differential Revision: https://reviews.llvm.org/D106519
In current implementation, if a regular task depends on a hidden helper task,
and when the hidden helper task is releasing its dependences, it directly calls
`__kmp_omp_task`. This could cause a problem that if `__kmp_push_task` returns
`TASK_NOT_PUSHED`, the task will be executed immediately. However, the hidden
helper threads are assumed to only execute hidden helper tasks. This could cause
problems because when calling `__kmp_omp_task`, the encountering gtid, which is
not the real one of the thread, is passed.
This patch uses `__kmp_give_task`, but because it is a static function, a new
wrapper `__kmpc_give_task` is added.
Reviewed By: AndreyChurbanov
Differential Revision: https://reviews.llvm.org/D106572
Standalone build for OpenMP runtime using GCC is giving -Wcomment
warnings where a backslash newline is encountered in the // style
comment. This switches the // style for /* style to silence the
warnings.
This patch includes a few changes to improve task allocation
performance slightly. These changes are enough to restore performance
drop observed after introducing hidden helper.
Differential Revision: https://reviews.llvm.org/D105715
There is no guarantee that the space allocated in `libname`
is enough to accomodate the whole `dl_info.dli_fname`,
because it could e.g. have an suffix - `.5`,
and that highlights another problem - what it should do about suffxies,
and should it do anything to resolve the symlinks before changing the filename?
```
$ LD_LIBRARY_PATH="$LD_LIBRARY_PATH:/usr/local/lib" ./src/utilities/rstest/rstest -c /tmp/f49137920.NEF
dl_info.dli_fname "/usr/local/lib/libomp.so.5"
strlen(dl_info.dli_fname) 26
lib_path_length 14
lib_path_length + 12 26
=================================================================
==30949==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x60300000002a at pc 0x000000548648 bp 0x7ffdfa0aa780 sp 0x7ffdfa0a9f40
WRITE of size 27 at 0x60300000002a thread T0
#0 0x548647 in strcpy (/home/lebedevri/rawspeed/build-Clang-SANITIZE/src/utilities/rstest/rstest+0x548647)
#1 0x7fb9e3e3d234 in ompd_init() /repositories/llvm-project/openmp/runtime/src/ompd-specific.cpp:102:5
#2 0x7fb9e3dcb446 in __kmp_do_serial_initialize() /repositories/llvm-project/openmp/runtime/src/kmp_runtime.cpp:6742:3
#3 0x7fb9e3dcb40b in __kmp_get_global_thread_id_reg /repositories/llvm-project/openmp/runtime/src/kmp_runtime.cpp:251:7
#4 0x59e035 in main /home/lebedevri/rawspeed/build-Clang-SANITIZE/../src/utilities/rstest/rstest.cpp:491
#5 0x7fb9e3762d09 in __libc_start_main csu/../csu/libc-start.c:308:16
#6 0x4df449 in _start (/home/lebedevri/rawspeed/build-Clang-SANITIZE/src/utilities/rstest/rstest+0x4df449)
0x60300000002a is located 0 bytes to the right of 26-byte region [0x603000000010,0x60300000002a)
allocated by thread T0 here:
#0 0x55cc5d in malloc (/home/lebedevri/rawspeed/build-Clang-SANITIZE/src/utilities/rstest/rstest+0x55cc5d)
#1 0x7fb9e3e3d224 in ompd_init() /repositories/llvm-project/openmp/runtime/src/ompd-specific.cpp:101:17
#2 0x7fb9e3762d09 in __libc_start_main csu/../csu/libc-start.c:308:16
SUMMARY: AddressSanitizer: heap-buffer-overflow (/home/lebedevri/rawspeed/build-Clang-SANITIZE/src/utilities/rstest/rstest+0x548647) in strcpy
Shadow bytes around the buggy address:
0x0c067fff7fb0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x0c067fff7fc0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x0c067fff7fd0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x0c067fff7fe0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x0c067fff7ff0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
=>0x0c067fff8000: fa fa 00 00 00[02]fa fa fa fa fa fa fa fa fa fa
0x0c067fff8010: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c067fff8020: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c067fff8030: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c067fff8040: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c067fff8050: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
Shadow byte legend (one shadow byte represents 8 application bytes):
Addressable: 00
Partially addressable: 01 02 03 04 05 06 07
Heap left redzone: fa
Freed heap region: fd
Stack left redzone: f1
Stack mid redzone: f2
Stack right redzone: f3
Stack after return: f5
Stack use after scope: f8
Global redzone: f9
Global init order: f6
Poisoned by user: f7
Container overflow: fc
Array cookie: ac
Intra object redzone: bb
ASan internal: fe
Left alloca redzone: ca
Right alloca redzone: cb
==30949==ABORTING
Aborted
```
The annotations in libomp were never built by default. The annotations are
also superseded by the annotations which the OMPT tool libarcher.so provides.
With respect to libarcher, libomp behaves as if libarcher would be the last
element of OMP_TOOL_LIBARARIES. I.e., if no other OMPT tool gets active,
libarcher will check if an OpenMP application is built with TSan.
Since libarcher gets loaded by default, enabling LIBOMP_TSAN_SUPPORT would
result in redundant annotations for TSan, which slightly differ in details
and coverage (e.g. task dependencies are not handled well by the annotations
in libomp).
This patch removes all TSan annotations from the OpenMP runtime code.
Differential Revision: https://reviews.llvm.org/D103767
This patch includes the following changes to address a few issues when
using hidden helper task.
- Assertion is triggered when there are inadvertent calls to hidden
helper functions on non-Linux OS
- Added deinit code in __kmp_internal_end_library function to fix random
shutdown crashes
- Moved task data access into the lock-guarded region in __kmp_push_task
Differential Revision: https://reviews.llvm.org/D105308
This reverts commit eab1fd389b.
This commit fixed a problem with 25073a4ecf (D103121) which is the one
we actually need to revert to unblock non-X86 builds of OpenMP. Can be
reapplied, or merged into, D103121 as it goes in again.
Normalized bounds of chunk of iterations to steal from are inclusive,
so upper bound should not be decremented in expression to check.
Problem was in attempt to steal iterations 0:0, that caused assertion after
wrong decrement. Reported in comment to https://reviews.llvm.org/D103648.
Differential Revision: https://reviews.llvm.org/D104880
Restructured dynamic loop dispatcher code.
Fixed use of dispatch buffers for nonmonotonic dynamic (static_steal) schedule:
- eliminated possibility of stealing iterations of the wrong loop when victim
thread changed its buffer to work on another loop;
- fixed race when victim thread changed its buffer to work in nested parallel;
- eliminated "static" property of the schedule, that is now a single thread can
execute whole loop.
Differential Revision: https://reviews.llvm.org/D103648
Two-level distributed barrier is a new experimental barrier designed
for Intel hardware that has better performance in some cases than the
default hyper barrier.
This barrier is designed to handle fine granularity parallelism where
barriers are used frequently with little compute and memory access
between barriers. There is no need to use it for codes with few
barriers and large granularity compute, or memory intensive
applications, as little difference will be seen between this barrier
and the default hyper barrier. This barrier is designed to work
optimally with a fixed number of threads, and has a significant setup
time, so should NOT be used in situations where the number of threads
in a team is varied frequently.
The two-level distributed barrier is off by default -- hyper barrier
is used by default. To use this barrier, you must set all barrier
patterns to use this type, because it will not work with other barrier
patterns. Thus, to turn it on, the following settings are required:
KMP_FORKJOIN_BARRIER_PATTERN=dist,dist
KMP_PLAIN_BARRIER_PATTERN=dist,dist
KMP_REDUCTION_BARRIER_PATTERN=dist,dist
Branching factors (set with KMP_FORKJOIN_BARRIER, KMP_PLAIN_BARRIER,
and KMP_REDUCTION_BARRIER) are ignored by the two-level distributed
barrier.
Differential Revision: https://reviews.llvm.org/D103121
Refactored code of dependence processing and added new inoutset dependence type.
Compiler can set dependence flag to 0x8 when call __kmpc_omp_task_with_deps.
All dependence flags library gets so far and corresponding dependence types:
1 - IN, 2 - OUT, 3 - INOUT, 4 - MUTEXINOUTSET, 8 - INOUTSET.
Differential Revision: https://reviews.llvm.org/D97085
Several variables were left unused as a result of different patches removing
their use.
Two variables have some use:
`poll_count` is used by the KMP_BLOCKING macro only under certain conditions.
Adding (void) to tell the compiler to ignore the unused variable.
`padding` is a dummy stack allocation with no intent to be used. Also adding
(void) to make the compiler ignore the unused variable.
Differential Revision: https://reviews.llvm.org/D104303
* Add GOMP versioned pause functions
* Add GOMP versioned affinity format functions
To do the affinity format functions, only attach versioned symbols
to the APPEND Fortran entries (e.g., omp_set_affinity_format_) since
GOMP only exports two symbols (one for Fortran, one for C). Our
affinity format functions have three symbols.
e.g., with omp_set_affinity_format:
1) omp_set_affinity_format (Fortran interface)
2) omp_set_affinity_format_ (Fortran interface)
3) ompc_set_affinity_format (C interface)
Have the GOMP version of the C symbol alias the ompc_* 3) version
instead of the Fortran unappended version 1).
Differential Revision: https://reviews.llvm.org/D103647
Remove strange checks for syscall() arguments where mask is NULL.
Valgrind reports these as error usages for the syscall.
Instead, just check if CACHE_LINE bytes is long enough. If not, then
search for the size. Also, by limiting the first size detection
attempt to CACHE_LINE bytes, instead of 1MB, we don't use more than one
cache line for the mask size. Before this patch, sometimes the returned
mask size was 640 bytes (10 cache lines) because the initial call to
getaffinity() was limited only by the internal kernel mask size
which can be very large.
Differential Revision: https://reviews.llvm.org/D103637
Lazily set affinity for root threads. Previously, the root thread
executing middle initialization would attempt to assign affinity
to other existing root threads. This was not working properly as the
set_system_affinity() function wasn't setting the affinity for the
target thread. Instead, the middle init thread was resetting the
its own affinity using the target thread's affinity mask.
Differential Revision: https://reviews.llvm.org/D103625
This is the first of seven patches that implements OMPD, a debugging interface to support debugging of OpenMP programs.
It contains support code required in "openmp/runtime" for OMPD implementation.
Reviewed By: @hbae
Differential Revision: https://reviews.llvm.org/D100181
Refactored code of dependence processing and added new inoutset dependence type.
Compiler can set dependence flag to 0x8 when call __kmpc_omp_task_with_deps.
Size of type of the dependence flag changed from 1 to 4 bytes in clang.
All dependence flags library gets so far and corresponding dependence types:
1 - IN, 2 - OUT, 3 - INOUT, 4 - MUTEXINOUTSET, 8 - INOUTSET.
Differential Revision: https://reviews.llvm.org/D97085
The ident_t * argument in __kmp_get_monotonicity was being used without
a customary NULL check, causing the function to crash in a Debug build.
Release builds were not affected thanks to dead store elimination.
Nesting mode is a new experimental feature in the OpenMP
runtime. It allows a user to set up nesting for an application in a
way that corresponds to the hardware topology levels on the machine an
application is being run on. For example, if a machine has 2 sockets,
each with 12 cores, then use of nesting mode could set up an outer
level of nesting that uses 2 threads per parallel region, and an inner
level of nesting that uses 12 threads per parallel region.
Nesting mode is controlled with the KMP_NESTING_MODE environment
variable as follows:
1) KMP_NESTING_MODE = 0: Nesting mode is off (default); max-active-levels-var
is set to 1 (the default -- nesting is off, nested parallel regions
are serialized).
2) KMP_NESTING_MODE = 1: Nesting mode is on, and a number of threads
will be assigned for each level discovered in the machine topology;
max-active-levels-var is set to the number of levels discovered.
3) KMP_NESTING_MODE = n, n>1: [Note: this option is experimental and may change
or be removed in the future.] Nesting mode is on, and a number of
threads will be assigned for each topology level discovered on the
machine, up to k<=n levels (since there may be fewer than n levels
discovered in the topology), and beyond the kth level, nested parallel
regions will be serialized; NOTE: max-active-levels-var is 1 (the default --
nesting is off, and nested parallel regions are serialized until the
user changes max-active-levels-var.
If the user sets OMP_NUM_THREADS or OMP_MAX_ACTIVE_LEVELS, they will
override KMP_NESTING_MODE settings for the associated environment
variables. The detected topology may be limited by an affinity mask
setting on the initial thread, or if the user sets KMP_HW_SUBSET. See
also: KMP_HOT_TEAMS_MAX_LEVEL for controlling use of hot teams for
nested parallel regions. Note that this feature only sets numbers of
threads used at nesting levels. The user should make use of
OMP_PLACES and OMP_PROC_BIND or KMP_AFFINITY for affinitizing those
threads, if desired.
Differential Revision: https://reviews.llvm.org/D102188
When on KNL and L2 or Tile layer is detected, manually add
the corresponding layer which is equivalent.
Differential Revision: https://reviews.llvm.org/D102865
Warnings on deprecated api cannot be suppressed if the library is not initialized.
With this change it is possible to set KMP_WARNINGS=false to suppress the warnings.
Differential Revision: https://reviews.llvm.org/D102676
Bug 49356 (https://bugs.llvm.org/show_bug.cgi?id=49356) reports crash in
the test case `tasking/bug_taskwait_detach.cpp`, which is caused by the wrong
function declaration. `gtid` in `__kmpc_omp_task` should be `kmp_int32`.
Reviewed By: AndreyChurbanov
Differential Revision: https://reviews.llvm.org/D102584
This is the first in a series of changes to the OpenMP runtime
that have been done internally by Microsoft. This patch makes
the necessary changes to enable libomp.dll to build with
the MSVC compiler targeting ARM64.
Differential Revision: https://reviews.llvm.org/D101173
When KMP_AFFINITY is set, each worker thread's gtid value is used as an
index into the place list to determine the thread's placement. With hidden
helpers enabled, this gtid value is shifted down leading to unexpected
shifted thread placement. This patch restores the previous behavior by
adjusting the mask index to take the number of hidden helper threads
into account.
Hidden helper threads are given the full initial mask and do not
participate in any of the other affinity mechanisms (place partitioning,
balanced affinity). Their affinity is only printed for debug builds.
Differential Revision: https://reviews.llvm.org/D101882
This patch does the following:
1) Introduce kmp_topology_t as the runtime-friendly structure (the
corresponding global variable is __kmp_topology) to determine the
exact machine topology which can vary widely among current and future
architectures. The current design is not easy to expand beyond the assumed
three layer topology: sockets, cores, and threads so a rework capable of
using the existing KMP_AFFINITY mechanisms is required.
This new topology structure has:
* The depth and types of the topology
* Ratio count for each consecutive level (e.g., number of cores per
socket, number of threads per core)
* Absolute count for each level (e.g., 2 sockets, 16 cores, 32 threads)
* Equivalent topology layer map (e.g., Numa domain is equivalent to
socket, L1/L2 cache equivalent to core)
* Whether it is uniform or not
The hardware threads are represented with the kmp_hw_thread_t
structure. This structure contains the ids (e.g., socket 0, core 1,
thread 0) and other information grabbed from the previous Address
structure. The kmp_topology_t structure contains an array of these.
2) Generalize the KMP_HW_SUBSET envirable for the new
kmp_topology_t structure. The algorithm doesn't assume any order with
tiles,numa domains,sockets,cores,threads. Instead it just parses the
envirable, makes sure it is consistent with the detected topology
(including taking into account equivalent layers) and then trims away
the unneeded subset of hardware threads. To enable this, a new
kmp_hw_subset_t structure is introduced which contains a vector of
items (hardware type, number user wants, offset). Any keyword within
__kmp_hw_get_keyword() can be used as a name and can be shortened as
well. e.g.,
KMP_HW_SUBSET=1s,2numa,4tile,2c,3t can be used on the KNL SNC-4 machine.
3) Simplify topology detection functions so they only do the singular
task of detecting the machine's topology. Printing, and all
canonicalizing functionality is now done afterwards. So many lines of
duplicated code are eliminated.
4) Add new ll_caches and numa_domains to OMP_PLACES, and
consequently, KMP_AFFINITY's granularity setting. All the names within
__kmp_hw_get_keyword() are available for use in OMP_PLACES or
KMP_AFFINITY's granularity setting.
5) Simplify and future-proof code where explicit lists of allowed
affinity settings keywords inside if() conditions.
6) Add x86 CPUID leaf 4 cache detection to existing x2apic id method
so equivalent caches could be detected (in particular for the ll_caches
place).
Differential Revision: https://reviews.llvm.org/D100997
Getting my feet wet here as a new committer.
Correct misspelling in check-depends.pl.
Reviewed By: vitalybuka
Differential Revision: https://reviews.llvm.org/D101552
Implement the remaining GOMP_* functions to support task reductions
in taskgroup, parallel, loop, and taskloop constructs. The unused mem
argument to many of the work-sharing constructs has to do with the
scan() directive/ inscan() modifier. If mem is set, each function
will call KMP_FATAL() and tell the user scan/inscan is unsupported. The
GOMP reduction implementation is kept separate from our implementation
because of how GOMP presents reduction data and computes the reductions.
GOMP expects the privatized copies to be present even after a #pragma
omp parallel reduction(task:...) region has ended so the data is stored
inside GOMP's uintptr_t* data pseudo-structure. This style is tightly
coupled with GCC compiler codegen. There also isn't any init(),
combiner(), fini() functions in GOMP's codegen so the two
implementations were to disparate to try to wrap GOMP's around our own.
Differential Revision: https://reviews.llvm.org/D98806
Current atfork() handler for child processes does not reset
the affinity masks array which prevents users from setting their own
affinity in child processes.
Differential Revision: https://reviews.llvm.org/D99218
omp_is_initial_device() is marked as a built-in function in the current
compiler, and user code guarded by this call may be optimized away,
resulting in undesired behavior in some cases. This patch provides a
possible fix for such cases by defining the routine as a variant
function and removing it from builtin list.
Differential Revision: https://reviews.llvm.org/D99447
The second argument to the strnlen_s(str, size) function should be
sizeof(str) when str is a true array of characters with known size
(instead of just a char*). Use type traits to determine if first
parameter is a character array and use the correct size based on that
trait.
Differential Revision: https://reviews.llvm.org/D98209
-- Added or moved checks to appropriate places.
-- Removed ineffective null check where the pointer is already being
dereferenced around the code.
-- Initialized variables that can be used without definitions.
-- Added call to dlclose/FreeLibrary in OMPT tool activation.
-- Added a new build compiler definition.
Differential Revision: https://reviews.llvm.org/D98584
It is reported that after enabling hidden helper thread, the program
can hit the assertion `new_gtid < __kmp_threads_capacity` sometimes. The root
cause is explained as follows. Let's say the default `__kmp_threads_capacity` is
`N`. If hidden helper thread is enabled, `__kmp_threads_capacity` will be offset
to `N+8` by default. If the number of threads we need exceeds `N+8`, e.g. via
`num_threads` clause, we need to expand `__kmp_threads`. In
`__kmp_expand_threads`, the expansion starts from `__kmp_threads_capacity`, and
repeatedly doubling it until the new capacity meets the requirement. Let's
assume the new requirement is `Y`. If `Y` happens to meet the constraint
`(N+8)*2^X=Y` where `X` is the number of iterations, the new capacity is not
enough because we have 8 slots for hidden helper threads.
Here is an example.
```
#include <vector>
int main(int argc, char *argv[]) {
constexpr const size_t N = 1344;
std::vector<int> data(N);
#pragma omp parallel for
for (unsigned i = 0; i < N; ++i) {
data[i] = i;
}
#pragma omp parallel for num_threads(N)
for (unsigned i = 0; i < N; ++i) {
data[i] += i;
}
return 0;
}
```
My CPU is 20C40T, then `__kmp_threads_capacity` is 160. After offset,
`__kmp_threads_capacity` becomes 168. `1344 = (160+8)*2^3`, then the assertions
hit.
Reviewed By: protze.joachim
Differential Revision: https://reviews.llvm.org/D98838
For clang this change is NFC cleanup, because clang
never calls atomic functions from runtime library.
Basically, pause is good in spin-loops waiting for something.
Atomic CAS loops do not wait for anything,
each CAS failure means some other thread progressed.
Performance experiments show that the pause only causes unnecessary slowdown
on CPUs with slow pause instruction, no difference on CPUs with fast pause
instruction, removal of the pause gives lesser binary size which is good.
Differential Revision: https://reviews.llvm.org/D97079
Restrict the chunk_size * chunk_num to only occur for valid
chunk_nums and reimplement calculating the limit to avoid overflow.
Differential Revision: https://reviews.llvm.org/D96747
and __kmpc_end_masked. The "master" construct is deprecated. Changed
proc-bind keyword from "master" to "primary". Use of both master
construct and master as proc-bind keyword is still allowed, but
deprecated.
Remove references to "master" in comments and strings, and replace
with "primary" or "primary thread". Function names and variables were
not touched, nor were references to deprecated master construct. These
can be updated over time. No new code should refer to master.
This is a preview of allocator support for target memory that depends on the
offload runtime API which allocates memory as described below.
llvm_omp_target_alloc_host(size_t size, int device_num);
-- Returns non-migratable memory owned by host.
-- Memory is accessible by host and device(s).
llvm_omp_target_alloc_shared(size_t size, int device_num);
-- Returns migratable memory owned by host and device.
-- Memory is accessible by host and device.
llvm_omp_target_alloc_device(size_t size, int device_num);
-- Returns memory owned by device.
-- Memory is only accessible by device.
New memory space and predefined allocator names are
-- llvm_omp_target_host_mem_space
-- llvm_omp_target_shared_mem_space
-- llvm_omp_target_device_mem_space
-- llvm_omp_target_host_mem_alloc
-- llvm_omp_target_shared_mem_alloc
-- llvm_omp_target_device_mem_alloc
Differential Revision: https://reviews.llvm.org/D96669
Cleanup changes:
- check value read from file;
- remove dead code;
- make unsigned variable to read hexadecimal number to;
- add debug assertion to check ref count.
Differential Revision: https://reviews.llvm.org/D96893
Stitching id could be overridden causing reference of destroyed object
when number of teams is 1. The patch separates stitching id store
location for teams and parallel nested in teams.
Differential Revision: https://reviews.llvm.org/D96562
Allow users to use a non-system version of perl, python and awk, which is useful
in certain package managers.
Reviewed By: JDevlieghere, MaskRay
Differential Revision: https://reviews.llvm.org/D95119
PR#49334 reports a crash when offloading to x86_64 with `target nowait`,
which is caused by referencing a nullptr. The root cause of the issue is, when
pushing a hidden helper task in `__kmp_push_task`, it also maps the gtid to its
shadow gtid, which is wrong.
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D97329
When including <ostream>, the register_callback macro of the OMPT callback.h
clashes with a function defined in ostream. This patch renames the macro
and includes ompt into the macro name.
This code alleviates some pathological loop parameters (lower,
upper, stride) within calculations involved in the static loop code. It
bounds the chunk size to the trip count if it is greater than the trip
count and also minimizes problematic code for when trip count < nth.
Differential Revision: https://reviews.llvm.org/D96426
Only attempt shutdown if lpReserved is NULL. The Windows documentation
states:
When handling DLL_PROCESS_DETACH, a DLL should free resources such as
heap memory only if the DLL is being unloaded dynamically (the
lpReserved parameter is NULL). If the process is terminating (the
lpReserved parameter is non-NULL), all threads in the process except the
current thread either have exited already or have been explicitly
terminated by a call to the ExitProcess function, which might leave some
process resources such as heaps in an inconsistent state. In this case,
it is not safe for the DLL to clean up the resources. Instead, the DLL
should allow the operating system to reclaim the memory.
Differential Revision: https://reviews.llvm.org/D96750
This patch limits the number of dispatch buffers (used for
loop worksharing construct) to between 1 and 4096.
Differential Revision: https://reviews.llvm.org/D96749
This silences warnings like these, in mingw builds with clang:
runtime/src/kmp_atomic.h:1021:13: warning: '__kmpc_atomic_cmplx8_rd' has C-linkage specified, but returns user-defined type 'kmp_cmplx64' (aka '__kmp_cmplx64_t') which is incompatible with C [-Wreturn-type-c-linkage]
runtime/src/z_Windows_NT_util.cpp:479:17: warning: cast from 'volatile void *' to 'type-parameter-0-0 *' drops volatile qualifier [-Wcast-qual]
flag = (C *)th->th.th_sleep_loc;
runtime/src/z_Windows_NT_util.cpp:1321:14: warning: cast to 'void *' from smaller integer type 'DWORD' (aka 'unsigned long') [-Wint-to-void-pointer-cast]
} else if ((void *)exit_val != (void *)th) {
Differential Revision: https://reviews.llvm.org/D96585
Add ifdefs around one function that only is used in unix build
configurations.
Add a void cast for a windows specific function that currently is
unused but may be intended to be used at some point.
Differential Revision: https://reviews.llvm.org/D96584
These variables are used only in certain build configurations,
or marked with a todo comment indicating that they should be
used/checked/reported.
Differential Revision: https://reviews.llvm.org/D96582
MinGW build configurations don't support this pragma (unless
compiling with clang, with -fms-extensions, and linking with
lld), and at least clang warns about it.
This library does end up linked by the cmake files anyway (as
long as the check works properly).
Differential Revision: https://reviews.llvm.org/D96581
check_library_exists fails for stdcall functions, because that
check doesn't include the necessary headers (and thus fails with
an undefined reference to _EnumProcessModules, when the import
library symbol actually is called _EnumProcessModules@16).
Merge the two previous checks check_include_files and
check_library_exists into one with check_c_source_compiles, and
merge the variables that indicate whether it succeeded.
Differential Revision: https://reviews.llvm.org/D96580
Three minor changes in this patch:
- added UNLIKELY hint to few rarely executed branches;
- replaced couple of run time checks with debug assertions;
- moved check of presence of ittnotify tool from inside the function call.
Differential Revision: https://reviews.llvm.org/D95816
This patch enables omp_get_num_devices() and omp_get_initial_device() on
Windows by providing an alternative to dlsym on Windows, and proposes to
add a new libomptarget entry, __tgt_get_num_devices().
Differential Revision: https://reviews.llvm.org/D96182
This patch adds lower-bound and upper-bound to num_teams clause
according to OpenMP 5.1 specification. The initial number of teams
created is implementation defined, but it will be greater than or
equal to lower-bound and less than or equal to upper-bound. If
num_teams clause is not specified, the number of teams created is
implementation defined, but it will be greater or equal to 1.
Differential Revision: https://reviews.llvm.org/D95820
New affinity patch introduced legitimate sign-compare warnings that
clang doesn't report but GCC-10 does. This removes the warnings by
changing two variables types to unsigned.
Differential Revision: https://reviews.llvm.org/D95818
This patch introduces a new environment variable to force monotonic
behavior for users that absolutely need it. This is in anticipation
of 5.0 change that uses non-monotonic behavior for dynamic scheduling
by default. Fixes for that and the actual switch are coming soon.
Differential Revision: https://reviews.llvm.org/D95263
Link error occurred when time profiling in libomp is enabled by default
because `libomp` is assumed to be a C library but the dependence on
`libLLVMSupport` for profiling is a C++ library. Currently the issue blocks all
OpenMP tests in Phabricator.
This patch set a new CMake option `OPENMP_ENABLE_LIBOMP_PROFILING` to
enable/disable the feature. By default it is disabled. Note that once time
profiling is enabled for `libomp`, it becomes a C++ library.
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D95585
When OMP_PLACES contains an invalid value, the warning informs the user
that the fallback is OMP_PLACES=threads, but the actual internal setting
is OMP_PLACES=cores and is detected as such with KMP_SETTINGS=1.
This patch informs the user that OMP_PLACES=cores is being used instead
of OMP_PLACES=threads.
Differential Revision: https://reviews.llvm.org/D95170
This patch adds the new algorithm for topology discovery using cpuid
leaf 1f. Only the new die level is detected and integrated into the
current affinity mechanisms including KMP_AFFINITY (granularity level
and compact/scatter algorithm), OMP_PLACES=dies, and KMP_HW_SUBSET.
Differential Revision: https://reviews.llvm.org/D95157
HWLOC 2.0 has numa nodes as separate children and are not in the main
parent/child topology tree anymore. This change takes this into
account. The main topology detection loop in the create_hwloc_map()
routine starts at a hardware thread within the initial affinity mask and
goes up the topology tree setting the socket/core/thread labels
correctly.
This change also introduces some of the more generic changes that the
future kmp_topology_t structure will take advantage of including a
generic ratio & count array (finding all ratios of topology layers like
threads/core cores/socket and finding all counts of each topology
layer), generic radix1 reduction step, generic uniformity check, and
generic printing of topology (en_US.txt)
Differential Revision: https://reviews.llvm.org/D95156
Problem reported by Joseph Shen <joseph.smeng@gmail.com>.
The patch changes *(&<atomic-var>) to (&<atomic-var>)->load().
Differential Revision: https://reviews.llvm.org/D95485
This patch sets the def-allocator-var ICV based on the environment variables
provided in OMP_ALLOCATOR. Previously, only allowed value for OMP_ALLOCATOR
was a predefined memory allocator. OpenMP 5.1 specification allows predefined
memory allocator, predefined mem space, or predefined mem space with traits in
OMP_ALLOCATOR. If an allocator can not be created using the provided environment
variables, the def-allocator-var is set to omp_default_mem_alloc.
Differential Revision: https://reviews.llvm.org/D94985
The basic design is to create an outer-most parallel team. It is not a regular team because it is only created when the first hidden helper task is encountered, and is only responsible for the execution of hidden helper tasks. We first use `pthread_create` to create a new thread, let's call it the initial and also the main thread of the hidden helper team. This initial thread then initializes a new root, just like what RTL does in initialization. After that, it directly calls `__kmpc_fork_call`. It is like the initial thread encounters a parallel region. The wrapped function for this team is, for main thread, which is the initial thread that we create via `pthread_create` on Linux, waits on a condition variable. The condition variable can only be signaled when RTL is being destroyed. For other work threads, they just do nothing. The reason that main thread needs to wait there is, in current implementation, once the main thread finishes the wrapped function of this team, it starts to free the team which is not what we want.
Two environment variables, `LIBOMP_NUM_HIDDEN_HELPER_THREADS` and `LIBOMP_USE_HIDDEN_HELPER_TASK`, are also set to configure the number of threads and enable/disable this feature. By default, the number of hidden helper threads is 8.
Here are some open issues to be discussed:
1. The main thread goes to sleeping when the initialization is finished. As Andrey mentioned, we might need it to be awaken from time to time to do some stuffs. What kind of update/check should be put here?
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D77609
The buckets are initialized in __kmp_dephash_create but when they are extended
the memory is allocated but not NULL'd, potentially leaving some buckets
uninitialized after all entries have been copied into the new allocation.
This commit makes sure the buckets are properly initialized with NULL before
copying the entries.
Differential Revision: https://reviews.llvm.org/D95167
Profiling has been recently implemented in libomptarget (D93055). This patch enables time profiling support for libomptarget in libomp, to support profiling of multi-threaded execution of offloaded regions.
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D94855
The basic design is to create an outer-most parallel team. It is not a regular team because it is only created when the first hidden helper task is encountered, and is only responsible for the execution of hidden helper tasks. We first use `pthread_create` to create a new thread, let's call it the initial and also the main thread of the hidden helper team. This initial thread then initializes a new root, just like what RTL does in initialization. After that, it directly calls `__kmpc_fork_call`. It is like the initial thread encounters a parallel region. The wrapped function for this team is, for main thread, which is the initial thread that we create via `pthread_create` on Linux, waits on a condition variable. The condition variable can only be signaled when RTL is being destroyed. For other work threads, they just do nothing. The reason that main thread needs to wait there is, in current implementation, once the main thread finishes the wrapped function of this team, it starts to free the team which is not what we want.
Two environment variables, `LIBOMP_NUM_HIDDEN_HELPER_THREADS` and `LIBOMP_USE_HIDDEN_HELPER_TASK`, are also set to configure the number of threads and enable/disable this feature. By default, the number of hidden helper threads is 8.
Here are some open issues to be discussed:
1. The main thread goes to sleeping when the initialization is finished. As Andrey mentioned, we might need it to be awaken from time to time to do some stuffs. What kind of update/check should be put here?
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D77609
Hierarchical barrier is an experimental barrier algorithm that uses aspects
of machine hierarchy to define the barrier tree structure. This patch fixes
offset calculation in hierarchical barrier. The offset is used to store info
on a flag about sleeping threads waiting on a location stored in the flag.
This commit also fixes a potential deadlock in hierarchical barrier when
using infinite blocktime by adjusting the offset value of leaf kids so that
it matches the value of leaf state. It also adds testing of default barriers
with infinite blocktime, and also tests hierarchical barrier algorithm with
both default and infinite blocktime.
Patch by Terry Wilmarth and Nawrin Sultana.
Differential Revision: https://reviews.llvm.org/D94241
This change enables volatile use of persistent memory for omp_large_cap_mem*
on supported systems. It depends on libmemkind's support for persistent memory,
and requirements/details can be found at the following url.
https://pmem.io/2020/01/20/memkind-dax-kmem.html
Differential Revision: https://reviews.llvm.org/D94353
Fugaku supercomputer is built with the Fujitsu A64FX microprocessor, whose cache line is 256. In current libomp, we only have cache line size 128 for PPC64 and otherwise 64. This patch added the support of cache line 256 for A64FX. It's worth noting that although A64FX is a variant of AArch64, this property is not shared. As a result, in light of UCX source code (392443ab92/src/ucs/arch/aarch64/cpu.c (L17)), we can only determine by checking whether the CPU is FUJITSU A64FX.
Reviewed By: jdoerfert, Hahnfeld
Differential Revision: https://reviews.llvm.org/D93169
This patch partially prepares the runtime source code to be built with
-Wconversion, which should trigger warnings if any implicit conversions
can possibly change a value. For builds done with icc or gcc, all such
warnings are handled in this patch. clang gives a much longer list of
warnings, particularly for sign conversions, which the other compilers
don't report. The -Wconversion flag is commented into cmake files, but
I'm not going to turn it on. If someone thinks it is important, and wants
to fix all the clang warnings, they are welcome to.
Types of changes made here involve either improving the consistency of types
used so that no conversion is needed, or else performing careful explicit
conversions, when we're sure a problem won't arise.
Patch is a combination of changes by Terry Wilmarth and Johnny Peyton.
Differential Revision: https://reviews.llvm.org/D92942
Introduce new kmp_safe_raii_file_t class with RAII semantics for file
open/close. It is essentially a wrapper around the C-style FILE* object.
This also unifies the way we error report if a file can't be opened.
Differential Revision: https://reviews.llvm.org/D92604
This patch enables serial initialization in the forked child process
to fix unstable runtime behavior when used with Python-based AI tools.
Differential Revision: https://reviews.llvm.org/D93230
This patch introduces a new RTM lock type based on spin lock which is
used for OMP lock with speculative hint on supported architecture.
Differential Revision: https://reviews.llvm.org/D92615
This patch adds new API __kmpc_taskloop_5 to accomadate strict
modifier (introduced in OpenMP 5.1) in num_tasks and grainsize
clause.
Differential Revision: https://reviews.llvm.org/D92352
KMP_AFFINITY=norespect was triggering an error because the underlying
process affinity mask was not updated to include the entire machine.
The Windows documentation states that the thread affinities must be
subsets of the process affinity. This patch also moves the printing
(for KMP_AFFINITY=verbose) of whether the initial mask was respected
out of each topology detection function and to one location where the
initial affinity mask is read.
Differential Revision: https://reviews.llvm.org/D92587
Check pointer returned by strchr, as it can be NULL in case of broken
format of input string. Introduced new function __kmp_str_loc_numbers
for fast parsing of numbers only in the location string.
Also made some cleanup of __kmp_str_loc_init declaration and usage:
- changed type of init_fname parameter to bool;
- changed input from true to false in places where fname is not used.
Differential Revision: https://reviews.llvm.org/D90962
D91692 missed various locations in kmp_gsupport, where the scope for
OMPT_STORE_RETURN_ADDRESS is too narrow, i.e. the scope ends before the OMPT
callback is called in some nested function.
This patch fixes the scoping issue, so that all OMPT tests pass, when the
tests are built with gcc.
Differential Revision: https://reviews.llvm.org/D92121
These changes add support for Intel's umonitor/umwait usage in wait
code, for architectures that support those intrinsic functions. Usage of
umonitor/umwait is off by default, but can be turned on by setting the
KMP_USER_LEVEL_MWAIT environment variable.
Differential Revision: https://reviews.llvm.org/D91189
Added UNLIKELY hint to one-time or rarely executed branches.
This improves performance of the library on some tasking benchmarks.
Differential Revision: https://reviews.llvm.org/D92322
With the change to using shared memory, there were a few problems that need to be fixed.
- The previous filename that was used for SHM only used process id. Given that process is
usually based on 16bit number, this was causing some conflicts on machines. Thus we add
UID to the name to prevent this.
- It appears under some conditions (SIGTERM, etc) the shared memory files were not getting
cleaned up. Added a call to clean up the shm files under those conditions. For this user
needs to set envirable KMP_HANDLE_SIGNALS to true.
Patch by Erdner, Todd <todd.erdner@intel.com>
Differential Revision: https://reviews.llvm.org/D91869
Once __kmp_task_finish is not executed for proxy tasks,
move mutexinoutset dependency code to __kmp_release_deps
which is executed for all task kinds.
Differential Revision: https://reviews.llvm.org/D92326
This is an alternative approach to address inconsistencies pointed out in: D90078
This patch makes sure that the return address is reset, when leaving the scope.
In some cases, I had to move the macro out of an if-statement to have it in the
right scope, in some cases I added an additional block to restrict the scope.
This patch does not handle inconsistencies, which might occur if the return
address is still set when we call into the application.
Test case (repeated_calls.c) provided by @hbae
Differential Revision: https://reviews.llvm.org/D91692
OpenMP 5.1 introduces the new env variable
OMP_TOOL_VERBOSE_INIT=(disabled|stdout|stderr|<filename>) to enable verbose
loading and initialization of OMPT tools.
This env variable helps to understand the cause when loading of a tool fails
(e.g., undefined symbols or dependency not in LD_LIBRARY_PATH)
Output of OMP_TOOL_VERBOSE_INIT is added for OMP_DISPLAY_ENV
Tests for this patch are integrated into the different existing tool loading
tests, making these tests more verbose. An Archer specific verbose test is
integrated into an existing Archer test.
Patch prepared by: Isabel Thärigen
Differential Revision: https://reviews.llvm.org/D91464
Adjusted external reference for Darwin/AARCH64 link compatibility.
Made size directive conditional only if __ELF__ defined.
Patch by Michael_Pique <mpique@icloud.com>
Differential Revision: https://reviews.llvm.org/D88252
Ye Luo