Now both method DispatchUnit::checkRAT() and DispatchUnit::canDispatch take as
input an Instruction refrence instead of an instruction descriptor.
This was requested by Simon in D44488 to simplify the diff.
llvm-svn: 327640
Before this patch, the register file was always updated at instruction creation
time. That means, new read-after-write dependencies, and new temporary registers
were allocated at instruction creation time.
This patch refactors the code in InstrBuilder, and move all the logic that
updates the register file into the dispatch unit. We only want to update the
register file when instructions are effectively dispatched (not before).
This refactoring also helps removing a bad dependency between the InstrBuilder
and the DispatchUnit.
No functional change intended.
llvm-svn: 327514
Since r327420, the tool can query the MCSchedModel interface to obtain the
reciprocal throughput information.
As a consequence, method `ResourceManager::getRThroughput`, and
method `Backend::getRThroughput` are no longer needed.
This patch simplifies the code by removing the custom RThroughput computation.
This patch also refactors class SummaryView by removing the dependency with
the Backend object.
No functional change intended.
llvm-svn: 327425
Summary: This is a first step towards making the pipeline configurable.
Subscribers: llvm-commits, andreadb
Differential Revision: https://reviews.llvm.org/D44309
llvm-svn: 327389
This change removes method Backend::getProcResourceMasks() and simplifies some
logic in the Views. This effectively removes yet another dependency between the
views and the Backend.
No functional change intended.
llvm-svn: 327214
This patch fixes a problem found when testing zero latency instructions on
target AArch64 -mcpu=exynos-m3 / -mcpu=exynos-m1.
On Exynos-m3/m1, direct branches are zero-latency instructions that don't consume
any processor resources. The DispatchUnit marks zero-latency instructions as
"executed", so that no scheduling is required. The event of instruction
executed is then notified to all the listeners, and the reorder buffer (managed
by the RetireControlUnit) is updated. In particular, the entry associated to the
zero-latency instruction in the reorder buffer is marked as executed.
Before this patch, the DispatchUnit forgot to assign a retire control unit token
(RCUToken) to the zero-latency instruction. As a consequence, the RCUToken was
used uninitialized. This was causing a crash in the RetireControlUnit logic.
Fixes PR36650.
llvm-svn: 327056
This allows the customization of the performance report.
Users can specify their own custom sequence of views.
Each view contributes a portion of the performance report generated by the
BackendPrinter.
Internally, class BackendPrinter keeps a sequence of views; views are printed
out in sequence when method 'printReport()' is called.
This patch addresses one of the two review comments from Clement in D43951.
llvm-svn: 327018
llvm-mca is an LLVM based performance analysis tool that can be used to
statically measure the performance of code, and to help triage potential
problems with target scheduling models.
llvm-mca uses information which is already available in LLVM (e.g. scheduling
models) to statically measure the performance of machine code in a specific cpu.
Performance is measured in terms of throughput as well as processor resource
consumption. The tool currently works for processors with an out-of-order
backend, for which there is a scheduling model available in LLVM.
The main goal of this tool is not just to predict the performance of the code
when run on the target, but also help with diagnosing potential performance
issues.
Given an assembly code sequence, llvm-mca estimates the IPC (instructions per
cycle), as well as hardware resources pressure. The analysis and reporting style
were mostly inspired by the IACA tool from Intel.
This patch is related to the RFC on llvm-dev visible at this link:
http://lists.llvm.org/pipermail/llvm-dev/2018-March/121490.html
Differential Revision: https://reviews.llvm.org/D43951
llvm-svn: 326998
Andrea Di Biagio