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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
63 lines
2.4 KiB
C++
63 lines
2.4 KiB
C++
//===-------- Benchmark memory specific tools -----------------------------===//
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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 "LibcMemoryBenchmark.h"
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#include "llvm/ADT/SmallVector.h"
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#include "llvm/Support/ErrorHandling.h"
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#include "llvm/Support/MathExtras.h"
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#include <algorithm>
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namespace llvm {
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namespace libc_benchmarks {
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// Returns a distribution that samples the buffer to satisfy the required
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// alignment.
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// When alignment is set, the distribution is scaled down by `Factor` and scaled
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// up again by the same amount during sampling.
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static std::uniform_int_distribution<uint32_t>
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GetOffsetDistribution(const StudyConfiguration &Conf) {
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if (Conf.AddressAlignment &&
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*Conf.AddressAlignment > AlignedBuffer::Alignment)
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report_fatal_error(
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"AddressAlignment must be less or equal to AlignedBuffer::Alignment");
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if (!Conf.AddressAlignment)
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return std::uniform_int_distribution<uint32_t>(0, 0); // Always 0.
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// If we test up to Size bytes, the returned offset must stay under
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// BuffersSize - Size.
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int64_t MaxOffset = Conf.BufferSize;
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MaxOffset -= Conf.Size.To;
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MaxOffset -= 1;
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if (MaxOffset < 0)
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report_fatal_error(
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"BufferSize too small to exercise specified Size configuration");
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MaxOffset /= Conf.AddressAlignment->value();
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return std::uniform_int_distribution<uint32_t>(0, MaxOffset);
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}
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OffsetDistribution::OffsetDistribution(const StudyConfiguration &Conf)
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: Distribution(GetOffsetDistribution(Conf)),
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Factor(Conf.AddressAlignment.valueOrOne().value()) {}
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// Precomputes offset where to insert mismatches between the two buffers.
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MismatchOffsetDistribution::MismatchOffsetDistribution(
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const StudyConfiguration &Conf)
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: MismatchAt(Conf.MemcmpMismatchAt) {
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if (MismatchAt <= 1)
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return;
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const auto ToSize = Conf.Size.To;
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for (size_t I = ToSize + 1; I < Conf.BufferSize; I += ToSize)
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MismatchIndices.push_back(I);
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if (MismatchIndices.empty())
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llvm::report_fatal_error("Unable to generate mismatch");
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MismatchIndexSelector =
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std::uniform_int_distribution<size_t>(0, MismatchIndices.size() - 1);
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}
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} // namespace libc_benchmarks
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} // namespace llvm
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