136 lines · cpp
1//===-- Benchmark memory specific tools -----------------------------------===//2//3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.4// See https://llvm.org/LICENSE.txt for license information.5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception6//7//===----------------------------------------------------------------------===//8 9#include "LibcMemoryBenchmark.h"10#include "llvm/ADT/SmallVector.h"11#include "llvm/ADT/Twine.h"12#include "llvm/Support/ErrorHandling.h"13#include "llvm/Support/MathExtras.h"14#include <algorithm>15 16namespace llvm {17namespace libc_benchmarks {18 19// Returns a distribution that samples the buffer to satisfy the required20// alignment.21// When alignment is set, the distribution is scaled down by `Factor` and scaled22// up again by the same amount during sampling.23static std::uniform_int_distribution<uint32_t>24getOffsetDistribution(size_t BufferSize, size_t MaxSizeValue,25 MaybeAlign AccessAlignment) {26 if (AccessAlignment && *AccessAlignment > AlignedBuffer::Alignment)27 report_fatal_error(28 "AccessAlignment must be less or equal to AlignedBuffer::Alignment");29 if (!AccessAlignment)30 return std::uniform_int_distribution<uint32_t>(0, 0); // Always 0.31 // If we test up to Size bytes, the returned offset must stay under32 // BuffersSize - Size.33 int64_t MaxOffset = BufferSize;34 MaxOffset -= MaxSizeValue;35 MaxOffset -= 1;36 if (MaxOffset < 0)37 report_fatal_error(38 "BufferSize too small to exercise specified Size configuration");39 MaxOffset /= AccessAlignment->value();40 return std::uniform_int_distribution<uint32_t>(0, MaxOffset);41}42 43OffsetDistribution::OffsetDistribution(size_t BufferSize, size_t MaxSizeValue,44 MaybeAlign AccessAlignment)45 : Distribution(46 getOffsetDistribution(BufferSize, MaxSizeValue, AccessAlignment)),47 Factor(AccessAlignment.valueOrOne().value()) {}48 49// Precomputes offset where to insert mismatches between the two buffers.50MismatchOffsetDistribution::MismatchOffsetDistribution(size_t BufferSize,51 size_t MaxSizeValue,52 size_t MismatchAt)53 : MismatchAt(MismatchAt) {54 if (MismatchAt <= 1)55 return;56 for (size_t i = MaxSizeValue + 1; i < BufferSize; i += MaxSizeValue)57 MismatchIndices.push_back(i);58 if (MismatchIndices.empty())59 report_fatal_error("Unable to generate mismatch");60 MismatchIndexSelector =61 std::uniform_int_distribution<size_t>(0, MismatchIndices.size() - 1);62}63 64static size_t getL1DataCacheSize() {65 const std::vector<CacheInfo> &CacheInfos = HostState::get().Caches;66 const auto IsL1DataCache = [](const CacheInfo &CI) {67 return CI.Type == "Data" && CI.Level == 1;68 };69 const auto CacheIt = find_if(CacheInfos, IsL1DataCache);70 if (CacheIt != CacheInfos.end())71 return CacheIt->Size;72 report_fatal_error("Unable to read L1 Cache Data Size");73}74 75static constexpr int64_t KiB = 1024;76static constexpr int64_t ParameterStorageBytes = 4 * KiB;77static constexpr int64_t L1LeftAsideBytes = 1 * KiB;78 79static size_t getAvailableBufferSize() {80 return getL1DataCacheSize() - L1LeftAsideBytes - ParameterStorageBytes;81}82 83ParameterBatch::ParameterBatch(size_t BufferCount)84 : BufferSize(getAvailableBufferSize() / BufferCount),85 BatchSize(ParameterStorageBytes / sizeof(ParameterType)),86 Parameters(BatchSize) {87 if (BufferSize <= 0 || BatchSize < 100)88 report_fatal_error("Not enough L1 cache");89 const size_t ParameterBytes = Parameters.size() * sizeof(ParameterType);90 const size_t BufferBytes = BufferSize * BufferCount;91 if (ParameterBytes + BufferBytes + L1LeftAsideBytes > getL1DataCacheSize())92 report_fatal_error(93 "We're splitting a buffer of the size of the L1 cache between a data "94 "buffer and a benchmark parameters buffer, so by construction the "95 "total should not exceed the size of the L1 cache");96}97 98size_t ParameterBatch::getBatchBytes() const {99 size_t BatchBytes = 0;100 for (auto &P : Parameters)101 BatchBytes += P.SizeBytes;102 return BatchBytes;103}104 105void ParameterBatch::checkValid(const ParameterType &P) const {106 if (P.OffsetBytes + P.SizeBytes >= BufferSize)107 report_fatal_error(108 llvm::Twine("Call would result in buffer overflow: Offset=")109 .concat(llvm::Twine(P.OffsetBytes))110 .concat(", Size=")111 .concat(llvm::Twine(P.SizeBytes))112 .concat(", BufferSize=")113 .concat(llvm::Twine(BufferSize)));114}115 116CopySetup::CopySetup()117 : ParameterBatch(2), SrcBuffer(ParameterBatch::BufferSize),118 DstBuffer(ParameterBatch::BufferSize) {}119 120MoveSetup::MoveSetup()121 : ParameterBatch(3), Buffer(ParameterBatch::BufferSize * 3) {}122 123ComparisonSetup::ComparisonSetup()124 : ParameterBatch(2), LhsBuffer(ParameterBatch::BufferSize),125 RhsBuffer(ParameterBatch::BufferSize) {126 // The memcmp buffers always compare equal.127 memset(LhsBuffer.begin(), 0xF, BufferSize);128 memset(RhsBuffer.begin(), 0xF, BufferSize);129}130 131SetSetup::SetSetup()132 : ParameterBatch(1), DstBuffer(ParameterBatch::BufferSize) {}133 134} // namespace libc_benchmarks135} // namespace llvm136