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https://github.com/Gericom/teak-llvm.git
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aba80d0734
Summary:
This patch adds a benchmarking infrastructure for llvm-libc memory functions.
In a nutshell, the code can benchmark small and large buffers for the memcpy, memset and memcmp functions.
It also produces graphs of size vs latency by running targets of the form `render-libc-{memcpy|memset|memcmp}-benchmark-{small|big}`.
The configurations are provided as JSON files and the benchmark also produces a JSON file.
This file is then parsed and rendered as a PNG file via the `render.py` script (make sure to run `pip3 install matplotlib scipy numpy`).
The script can take several JSON files as input and will superimpose the curves if they are from the same host.
TODO:
- The code benchmarks whatever is available on the host but should be configured to benchmark the -to be added- llvm-libc memory functions.
- Add a README file with instructions and rationale.
- Produce scores to track the performance of the functions over time to allow for regression detection.
Reviewers: sivachandra, ckennelly
Subscribers: mgorny, MaskRay, libc-commits
Tags: #libc-project
Differential Revision: https://reviews.llvm.org/D72516
88 lines
2.8 KiB
C++
88 lines
2.8 KiB
C++
//===-------- Benchmark memcmp implementation -----------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#include "LibcBenchmark.h"
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#include "LibcMemoryBenchmark.h"
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#include "LibcMemoryBenchmarkMain.h"
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#include "llvm/ADT/StringSwitch.h"
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#include "llvm/Support/raw_ostream.h"
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namespace llvm {
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namespace libc_benchmarks {
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// The context encapsulates the buffers, parameters and the measure.
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struct MemcmpContext : public BenchmarkRunner {
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using FunctionPrototype = int (*)(const void *, const void *, size_t);
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struct ParameterType {
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uint16_t Offset = 0;
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};
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explicit MemcmpContext(const StudyConfiguration &Conf)
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: MOD(Conf), OD(Conf), ABuffer(Conf.BufferSize), BBuffer(Conf.BufferSize),
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PP(*this) {
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std::uniform_int_distribution<char> Dis;
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// Generate random buffer A.
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for (size_t I = 0; I < Conf.BufferSize; ++I)
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ABuffer[I] = Dis(Gen);
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// Copy buffer A to B.
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::memcpy(BBuffer.begin(), ABuffer.begin(), Conf.BufferSize);
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if (Conf.MemcmpMismatchAt == 0)
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return; // all same.
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else if (Conf.MemcmpMismatchAt == 1)
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for (char &c : BBuffer)
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++c; // all different.
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else
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for (const auto I : MOD.getMismatchIndices())
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++BBuffer[I];
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}
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// Needed by the ParameterProvider to update the current batch of parameter.
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void Randomize(MutableArrayRef<ParameterType> Parameters) {
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if (MOD)
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for (auto &P : Parameters)
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P.Offset = MOD(Gen, CurrentSize);
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else
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for (auto &P : Parameters)
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P.Offset = OD(Gen);
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}
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ArrayRef<StringRef> getFunctionNames() const override {
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static std::array<StringRef, 1> kFunctionNames = {"memcmp"};
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return kFunctionNames;
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}
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BenchmarkResult benchmark(const BenchmarkOptions &Options,
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StringRef FunctionName, size_t Size) override {
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CurrentSize = Size;
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// FIXME: Add `bcmp` once we're guaranteed that the function is provided.
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FunctionPrototype Function =
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StringSwitch<FunctionPrototype>(FunctionName).Case("memcmp", &::memcmp);
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return llvm::libc_benchmarks::benchmark(
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Options, PP, [this, Function, Size](ParameterType p) {
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return Function(ABuffer + p.Offset, BBuffer + p.Offset, Size);
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});
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}
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private:
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std::default_random_engine Gen;
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MismatchOffsetDistribution MOD;
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OffsetDistribution OD;
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size_t CurrentSize = 0;
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AlignedBuffer ABuffer;
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AlignedBuffer BBuffer;
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SmallParameterProvider<MemcmpContext> PP;
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};
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std::unique_ptr<BenchmarkRunner> getRunner(const StudyConfiguration &Conf) {
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return std::make_unique<MemcmpContext>(Conf);
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}
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} // namespace libc_benchmarks
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} // namespace llvm
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