This patch adds initial vector extension support to RISC-V's exegesis.
The strategy here is to enumerate all RVV _pseudo_ opcodes as their MC
opcode counterparts are kind of useless under this circumstance. We also
enumerate all possible VTYPE operands in each CodeTemplate
configuration. Various of MachineFunction Passes are used for post
processing the snippets, like inserting VSETVLI instructions.
See https://llvm.org/devmtg/2024-10/slides/techtalk/Hsu-RVV-Exegesis.pdf
for more technical details.
Some of this was needed to fix implicit conversions from MCRegister to
unsigned when calling getReg() on MCOperand for example.
The majority was done by reviewing parts of the code that dealt with
registers, converting them to MCRegister and then seeing what new
implicit conversions were created and fixing those.
There were a few places where I used MCPhysReg instead of MCRegiser for
static arrays since its uint16_t instead of unsigned.
This relands f8f8598fd886cddfd374fa43eb6d7d37d301b576
Follow up on #122371:
The problem here is a little subtle: when we dry-run the measurement
phase, we create a LLJIT instance without actually executing the
snippets. The key is, LLJIT has its own TargetMachine which uses triple
designated by LLVM_TARGET_ARCH (which is default to host). On a machine
that does not support Exegesis, the LLJIT would fail to create its
TargetMachine because llvm-exegesis don't even register the host's
target!
Putting this test into any of the target-specific folder won't help,
because it's about the host. And personally I don't really want to use
`exegesis-can-execute-<arch>` for generic tests like this -- it's too
strict as we don't actually need to execute the snippet.
My solution here is creating another test feature which is added only
when LLVM_TARGET_ARCH is supported by llvm-exegesis. This feature is
something in between `<arch>-registered-target` and
`exegesis-can-execute-<arch>`.
…#121991)"
This reverts commit f8f8598fd886cddfd374fa43eb6d7d37d301b576.
This breaks ARMv7 and s390x buildbot with the following message:
```
llvm-exegesis error: No available targets are compatible with triple "armv8l-unknown-linux-gnueabihf"
FileCheck error: '<stdin>' is empty.
FileCheck command line: /home/tcwg-buildbot/worker/clang-armv7-2stage/stage2/bin/FileCheck /home/tcwg-buildbot/worker/clang-armv7-2stage/llvm/llvm/test/tools/llvm-exegesis/dry-run-measurement.test
```
With the new benchmark phase, `dry-run-measurement`, llvm-exegesis can
run everything except the actual snippet execution. It is useful when we
want to test some parts of the code between the `assemble-measured-code`
and `measure` phase without actually running on native platforms.
This patch removes the llvm:: prefix within llvm-exegesis where it is
not necessary. This is most occurrences of the prefix within exegesis as
exegesis is within the llvm namespace. This patch makes things more
consistent as the vast majority of the code did not use the llvm::
prefix for anything.
This patch adds support for validation counters. Validation counters can
be used to measure events that occur during snippet execution like cache
misses to ensure that certain assumed invariants about the benchmark
actually hold. Validation counters are setup within a perf event group,
so are turned on and off at exactly the same time as the "group leader"
counter that measures the desired value.
This refactoring gets things ready for validation counters where the
plan is to reuse the existing Counter infrastructure to contain event
groups that consist of a single event that is being measured along with
validation counters.
This patch adds support in the llvm-exegesis tablegen emitter for
validation counters. Full support for validation counters in
llvm-exegesis will be added in a future patch.
Currently, the llvm-exegesis LatencyBenchmarkRunner repeats the
benchmark several times (currently 30) and then aggregates the result to
deal with noise in the measurement process. With this patch, the number
of repetitions to perform is made configurable rather than left as a
static number. This allows for significantly faster execution in
situations where someone is performing a task like experimenting with
memory annotations where the exact cycle counts might not be useful, and
also allows for increased precision when desired.
When generating snippets for AArch64 with --opcode-index=-1, the code
generator asserts on opcodes that are not supported according to CPU
features.
The same assertion can be triggered even when generating a serial
snippet for a supported opcode if SERIAL_VIA_NON_MEMORY_INSTR execution
mode is used and an unsupported instruction is chosen as the "other
instruction". Unlike the first case, this one may result in flaky
failures because the other instruction is randomly chosen from the
instructions suitable for serializing execution.
This patch adjusts TableGen emitter for *GenInstrInfo.inc to make
possible to query for opcode availability instead of just asserting on
unsupported ones.
~~
Huawei RRI, OS Lab
Reviewed By: courbet
Differential Revision: https://reviews.llvm.org/D146303
This patch gives the ability to assign performance counters within
llvm-exegesis to a specific process by passing its PID. This is needed
later on for implementing a subprocess executor. Defaults to zero, the
current process, for the InProcessFunctionExecutorImpl.
Reviewed By: courbet
Differential Revision: https://reviews.llvm.org/D151020
Revert "[llvm-exegesis] Introduce Subprocess Executor Mode"
This reverts commit 5e9173c43a9b97c8614e36d6f754317f731e71e9.
This reverts commit 4d618b52f6e05e41d35f56653cb36bf7d4dc794e.
Reverting the PID commit as it is currently breaking MinGW builds and
the way I'm checking for the presence of pid_t needs to be fixed and I
need to do some testing. The subprocess executor mode patch is a
dependent patch so also needs to be reverted and also needs some work as
it is currently failing tests where libpfm is installed and the kernel
version is less than 5.6.
This patch gives the ability to assign performance counters within
llvm-exegesis to a specific process by passing its PID. This is needed
later on for implementing a subprocess executor. Defaults to zero, the
current process, for the InProcessFunctionExecutorImpl.
Reviewed By: courbet
Differential Revision: https://reviews.llvm.org/D151020
In order to better support adding in new implementations of
FunctionExecutor, this patch makes some small changes so that it is
easier to add new ones in. FunctionExecutorImpl is renamed to
InProcessFunctionExecutorImpl to better reflect how it will be placed
relative to the soon-to-be introduced subprocess executor and a new
function is created to create executors so selection can be done more
easily. In addition, a new CLI flag, -execution-mode, which can be used
to select between the different executors.
Reviewed By: courbet
Differential Revision: https://reviews.llvm.org/D151019
Performance counters may be unavailable due to various reasons (such as
access restriction via sysctl properties or the CPU model being unknown
to libpfm). On the other hand, for debugging llvm-exegesis itself it is
still useful to be able to run generated code snippets to ensure that
the snippet does not crash at run time.
The --use-dummy-perf-counters command line option makes llvm-exegesis
behave just as usual except for using fake event counts instead of asking
the kernel for actual values.
~~
Huawei RRI, OS Lab
Reviewed By: courbet
Differential Revision: https://reviews.llvm.org/D146301
When llvm-exegesis was first introduced, it only supported benchmarking
individual instructions, hence the name for the data structure storing
the data corresponding to a benchmark being called InstructionBenchmark
made sense. However, now that benchmarking arbitrary snippets is
supported, InstructionBenchmark doesn't correspond to a single
instruction. This patch refactors InstructionBenchmark to be called
Benchmark to clean up this little bit of technical debt.
Reviewed By: courbet
Differential Revision: https://reviews.llvm.org/D146884
While "skip measurements mode" is super useful for test coverage,
i've come to discover it's trade-offs. It still calls back-end
to actually codegen the target assembly, and that is what is taking
80%+ of the time regardless of whether or not we skip the measurements.
On the other hand, just being able to see that exegesis can come up
with a snippet to measure something, is already very useful,
and takes maybe a second for a all-opcode sweep.
Reviewed By: gchatelet
Differential Revision: https://reviews.llvm.org/D140702
Sometimes we only want to ensure that we can produce snippets (all the way
through `SnippetRepetitor`!), but don't care for the execution.
E.g. all of our tests are this way.
I've built LLVM without PFM and removed my CPU from `X86PfmCounters.td`,
and this produces the expected results in that configuration.
Reviewed By: courbet
Differential Revision: https://reviews.llvm.org/D139448
The X86 exegesis target is never executed run on non-X86 hosts, disable
X86 instrinsic code on non-X86 targets.
This reverts commit 8cfc872129a99782ab07a19171bf8eace85589ae.
Use `__builtin_ia32_fxsave64` under __GNUC__, (_fxsave64) does not exist in old versions of
gcc (pre-9.1).
This reverts commit e128f9cafca4e72b089fcd1381af5a1ec656d987.
LBR contains (up to) 16 entries for last x branches and the X86LBRCounter (from D77422) should be able to return all those.
Currently, it just returns the latest entry, which could lead to mis-leading measurements.
This patch aslo changes the LatencyBenchmarkRunner to accommodate multi-value readings.
https://reviews.llvm.org/D81050
Summary:
Using a .data() member on a StringRef was discarding the StringRef
size, breaking llvm-exegesis on machines with counter sums (e.g.
Zen2).
Reviewers: oontvoo
Subscribers: mstojanovic, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D80982
It can be used to avoid passing the begin and end of a range.
This makes the code shorter and it is consistent with another
wrappers we already have.
Differential revision: https://reviews.llvm.org/D78016
Summary: Commit 141915963b6ab36ee4e577d1b27673fa4d05b409 was reverted in
abe01e17f648a97666d4fbed41f0861686a17972 because it broke builds testing
without libpfm. A preparatory commit <commit_sha1> was added to enable
this recommit.
Original commit message:
Followup to D74085.
Replace the use of `report_fatal_error()` with returning the error to
`llvm-exegesis.cpp` and handling it there.
Differential Revision: https://reviews.llvm.org/D74113
It broke e.g. all tests under tools/llvm-exegesis/X86/ when libpfm is
not available, see comment on D74085.
This reverts commit b3576f60ebc8f660afad8120a72473be47517573 and
141915963b6ab36ee4e577d1b27673fa4d05b409.
Followup to D74085.
Replace the use of `report_fatal_error()` with returning the error to
`llvm-exegesis.cpp` and handling it there.
Differential Revision: https://reviews.llvm.org/D74113
Summary:
... instead of crashing.
On typical exmaple is when there are no available registers.
Reviewers: gchatelet
Subscribers: tschuett, mstojanovic, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D73196
The addition of `inverse_throughput` mode highlighted the disjointedness
of snippet generators and benchmark runners because it used the
`UopsSnippetGenerator` with the `LatencyBenchmarkRunner`.
To keep the code consistent tie the snippet generators to
parallelization/serialization rather than their benchmark runners.
Renaming `LatencySnippetGenerator` -> `SerialSnippetGenerator`.
Renaming `UopsSnippetGenerator` -> `ParallelSnippetGenerator`.
Differential Revision: https://reviews.llvm.org/D72928
Check if the appropriate counters for the specified mode are defined on
the target. This is checked before any other work is done.
Differential Revision: https://reviews.llvm.org/D71927
Summary:
This adds a `-max-configs-per-opcode` option to limit the number of
configs per opcode.
Reviewers: gchatelet
Subscribers: tschuett, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D68642
llvm-svn: 374054
Now that we've moved to C++14, we no longer need the llvm::make_unique
implementation from STLExtras.h. This patch is a mechanical replacement
of (hopefully) all the llvm::make_unique instances across the monorepo.
llvm-svn: 369013
Summary:
D60041 / D60138 refactoring changed how CMOV/SETcc opcodes
are handled. concode is now an immediate, with it's own operand type.
This at least allows to not crash on the opcode.
However, this still won't generate all the snippets
with all the condcode enumerators. D60066 does that.
Reviewers: courbet, gchatelet
Reviewed By: gchatelet
Subscribers: tschuett, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D60057
llvm-svn: 357841
to reflect the new license.
We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.
Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.
llvm-svn: 351636
Summary:
This simplifies the code and moves everything to tablegen for consistency. This
also prepares the ground for adding issue counters.
Reviewers: gchatelet, john.brawn, jsji
Subscribers: nemanjai, mgorny, javed.absar, kbarton, tschuett, llvm-commits
Differential Revision: https://reviews.llvm.org/D54297
llvm-svn: 346489
Summary:
The pfm counters are now in the ExegesisTarget rather than the
MCSchedModel (PR39165).
This also compresses the pfm counter tables (PR37068).
Reviewers: RKSimon, gchatelet
Subscribers: mgrang, llvm-commits
Differential Revision: https://reviews.llvm.org/D52932
llvm-svn: 345243
