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Diffstat (limited to 'xpcom/rust/gtest/bench-collections/Bench.cpp')
| -rw-r--r-- | xpcom/rust/gtest/bench-collections/Bench.cpp | 297 |
1 files changed, 297 insertions, 0 deletions
diff --git a/xpcom/rust/gtest/bench-collections/Bench.cpp b/xpcom/rust/gtest/bench-collections/Bench.cpp new file mode 100644 index 0000000000..0035d27ed6 --- /dev/null +++ b/xpcom/rust/gtest/bench-collections/Bench.cpp @@ -0,0 +1,297 @@ +/* This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ + +// Overview +// -------- +// This file measures the speed of various implementations of C++ and Rust +// collections (hash tables, etc.) used within the codebase. There are a small +// number of benchmarks for each collection type; each benchmark tests certain +// operations (insertion, lookup, iteration, etc.) More benchmarks could easily +// be envisioned, but this small number is enough to characterize the major +// differences between implementations, while keeping the file size and +// complexity low. +// +// Details +// ------- +// The file uses `MOZ_GTEST_BENCH_F` so that results are integrated into +// PerfHerder. It is also designed so that individual test benchmarks can be +// run under a profiler. +// +// The C++ code uses `MOZ_RELEASE_ASSERT` extensively to check values and +// ensure operations aren't optimized away by the compiler. The Rust code uses +// `assert!()`. These should be roughly equivalent, but aren't guaranteed to be +// the same. As a result, the intra-C++ comparisons should be reliable, and the +// intra-Rust comparisons should be reliable, but the C++ vs. Rust comparisons +// may be less reliable. +// +// Note that the Rust implementations run very slowly without --enable-release. +// +// Profiling +// --------- +// If you want to measure a particular implementation under a profiler such as +// Callgrind, do something like this: +// +// MOZ_RUN_GTEST=1 GTEST_FILTER='*BenchCollections*$IMPL*' +// valgrind --tool=callgrind --callgrind-out-file=clgout +// $OBJDIR/dist/bin/firefox -unittest +// callgrind_annotate --auto=yes clgout > clgann +// +// where $IMPL is part of an implementation name in a test (e.g. "PLDHash", +// "MozHash") and $OBJDIR is an objdir containing a --enable-release build. +// +// Note that multiple processes are spawned, so `clgout` gets overwritten +// multiple times, but the last process to write its profiling data to file is +// the one of interest. (Alternatively, use --callgrind-out-file=clgout.%p to +// get separate output files for each process, with a PID suffix.) + +#include "gtest/gtest.h" +#include "gtest/MozGTestBench.h" // For MOZ_GTEST_BENCH +#include "mozilla/AllocPolicy.h" +#include "mozilla/ArrayUtils.h" +#include "mozilla/HashFunctions.h" +#include "mozilla/HashTable.h" +#include "mozilla/StaticMutex.h" +#include "mozilla/TimeStamp.h" +#include "PLDHashTable.h" +#include <unordered_set> + +using namespace mozilla; + +// This function gives a pseudo-random sequence with the following properties: +// - Deterministic and platform-independent. +// - No duplicates in the first VALS_LEN results, which is useful for ensuring +// the tables get to a particular size, and also for guaranteeing lookups +// that fail. +static uintptr_t MyRand() { + static uintptr_t s = 0; + s = s * 1103515245 + 12345; + return s; +} + +// Keep this in sync with Params in bench.rs. +struct Params { + const char* mConfigName; + size_t mNumInserts; // Insert this many unique keys + size_t mNumSuccessfulLookups; // Does mNumInserts lookups each time + size_t mNumFailingLookups; // Does mNumInserts lookups each time + size_t mNumIterations; // Iterates the full table each time + bool mRemoveInserts; // Remove all entries at end? +}; + +// We don't use std::unordered_{set,map}, but it's an interesting thing to +// benchmark against. +// +// Keep this in sync with all the other Bench_*() functions. +static void Bench_Cpp_unordered_set(const Params* aParams, void** aVals, + size_t aLen) { + std::unordered_set<void*> hs; + + for (size_t j = 0; j < aParams->mNumInserts; j++) { + hs.insert(aVals[j]); + } + + for (size_t i = 0; i < aParams->mNumSuccessfulLookups; i++) { + for (size_t j = 0; j < aParams->mNumInserts; j++) { + MOZ_RELEASE_ASSERT(hs.find(aVals[j]) != hs.end()); + } + } + + for (size_t i = 0; i < aParams->mNumFailingLookups; i++) { + for (size_t j = aParams->mNumInserts; j < aParams->mNumInserts * 2; j++) { + MOZ_RELEASE_ASSERT(hs.find(aVals[j]) == hs.end()); + } + } + + for (size_t i = 0; i < aParams->mNumIterations; i++) { + size_t n = 0; + for (const auto& elem : hs) { + (void)elem; + n++; + } + MOZ_RELEASE_ASSERT(aParams->mNumInserts == n); + MOZ_RELEASE_ASSERT(hs.size() == n); + } + + if (aParams->mRemoveInserts) { + for (size_t j = 0; j < aParams->mNumInserts; j++) { + MOZ_RELEASE_ASSERT(hs.erase(aVals[j]) == 1); + } + MOZ_RELEASE_ASSERT(hs.size() == 0); + } else { + MOZ_RELEASE_ASSERT(hs.size() == aParams->mNumInserts); + } +} + +// Keep this in sync with all the other Bench_*() functions. +static void Bench_Cpp_PLDHashTable(const Params* aParams, void** aVals, + size_t aLen) { + PLDHashTable hs(PLDHashTable::StubOps(), sizeof(PLDHashEntryStub)); + + for (size_t j = 0; j < aParams->mNumInserts; j++) { + auto entry = static_cast<PLDHashEntryStub*>(hs.Add(aVals[j])); + MOZ_RELEASE_ASSERT(!entry->key); + entry->key = aVals[j]; + } + + for (size_t i = 0; i < aParams->mNumSuccessfulLookups; i++) { + for (size_t j = 0; j < aParams->mNumInserts; j++) { + MOZ_RELEASE_ASSERT(hs.Search(aVals[j])); + } + } + + for (size_t i = 0; i < aParams->mNumFailingLookups; i++) { + for (size_t j = aParams->mNumInserts; j < aParams->mNumInserts * 2; j++) { + MOZ_RELEASE_ASSERT(!hs.Search(aVals[j])); + } + } + + for (size_t i = 0; i < aParams->mNumIterations; i++) { + size_t n = 0; + for (auto iter = hs.Iter(); !iter.Done(); iter.Next()) { + n++; + } + MOZ_RELEASE_ASSERT(aParams->mNumInserts == n); + MOZ_RELEASE_ASSERT(hs.EntryCount() == n); + } + + if (aParams->mRemoveInserts) { + for (size_t j = 0; j < aParams->mNumInserts; j++) { + hs.Remove(aVals[j]); + } + MOZ_RELEASE_ASSERT(hs.EntryCount() == 0); + } else { + MOZ_RELEASE_ASSERT(hs.EntryCount() == aParams->mNumInserts); + } +} + +// Keep this in sync with all the other Bench_*() functions. +static void Bench_Cpp_MozHashSet(const Params* aParams, void** aVals, + size_t aLen) { + mozilla::HashSet<void*, mozilla::DefaultHasher<void*>, MallocAllocPolicy> hs; + + for (size_t j = 0; j < aParams->mNumInserts; j++) { + MOZ_RELEASE_ASSERT(hs.put(aVals[j])); + } + + for (size_t i = 0; i < aParams->mNumSuccessfulLookups; i++) { + for (size_t j = 0; j < aParams->mNumInserts; j++) { + MOZ_RELEASE_ASSERT(hs.has(aVals[j])); + } + } + + for (size_t i = 0; i < aParams->mNumFailingLookups; i++) { + for (size_t j = aParams->mNumInserts; j < aParams->mNumInserts * 2; j++) { + MOZ_RELEASE_ASSERT(!hs.has(aVals[j])); + } + } + + for (size_t i = 0; i < aParams->mNumIterations; i++) { + size_t n = 0; + for (auto iter = hs.iter(); !iter.done(); iter.next()) { + n++; + } + MOZ_RELEASE_ASSERT(aParams->mNumInserts == n); + MOZ_RELEASE_ASSERT(hs.count() == n); + } + + if (aParams->mRemoveInserts) { + for (size_t j = 0; j < aParams->mNumInserts; j++) { + hs.remove(aVals[j]); + } + MOZ_RELEASE_ASSERT(hs.count() == 0); + } else { + MOZ_RELEASE_ASSERT(hs.count() == aParams->mNumInserts); + } +} + +extern "C" { +void Bench_Rust_HashSet(const Params* params, void** aVals, size_t aLen); +void Bench_Rust_FnvHashSet(const Params* params, void** aVals, size_t aLen); +void Bench_Rust_FxHashSet(const Params* params, void** aVals, size_t aLen); +} + +static const size_t VALS_LEN = 131072; + +// Each benchmark measures a different aspect of performance. +// Note that no "Inserts" value can exceed VALS_LEN. +// Also, if any failing lookups are done, Inserts must be <= VALS_LEN/2. +const Params gParamsList[] = { + // clang-format off + // Successful Failing Remove + // Inserts lookups lookups Iterations inserts + { "succ_lookups", 1024, 5000, 0, 0, false }, + { "fail_lookups", 1024, 0, 5000, 0, false }, + { "insert_remove", VALS_LEN, 0, 0, 0, true }, + { "iterate", 1024, 0, 0, 5000, false }, + // clang-format on +}; + +class BenchCollections : public ::testing::Test { + protected: + void SetUp() override { + StaticMutexAutoLock lock(sValsMutex); + + if (!sVals) { + sVals = (void**)malloc(VALS_LEN * sizeof(void*)); + for (size_t i = 0; i < VALS_LEN; i++) { + // This leaves the high 32 bits zero on 64-bit platforms, but that + // should still be enough randomness to get typical behaviour. + sVals[i] = reinterpret_cast<void*>(uintptr_t(MyRand())); + } + } + + printf("\n"); + for (size_t i = 0; i < ArrayLength(gParamsList); i++) { + const Params* params = &gParamsList[i]; + printf("%14s", params->mConfigName); + } + printf("%14s\n", "total"); + } + + public: + void BenchImpl(void (*aBench)(const Params*, void**, size_t)) { + StaticMutexAutoLock lock(sValsMutex); + + double total = 0; + for (size_t i = 0; i < ArrayLength(gParamsList); i++) { + const Params* params = &gParamsList[i]; + TimeStamp t1 = TimeStamp::Now(); + aBench(params, sVals, VALS_LEN); + TimeStamp t2 = TimeStamp::Now(); + double t = (t2 - t1).ToMilliseconds(); + printf("%11.1f ms", t); + total += t; + } + printf("%11.1f ms\n", total); + } + + private: + // Random values used in the benchmarks. + static void** sVals MOZ_GUARDED_BY(sValsMutex); + + // A mutex that protects all benchmark operations, ensuring that two + // benchmarks never run concurrently. + static StaticMutex sValsMutex; +}; + +void** BenchCollections::sVals; +StaticMutex BenchCollections::sValsMutex; + +MOZ_GTEST_BENCH_F(BenchCollections, unordered_set, + [this] { BenchImpl(Bench_Cpp_unordered_set); }); + +MOZ_GTEST_BENCH_F(BenchCollections, PLDHash, + [this] { BenchImpl(Bench_Cpp_PLDHashTable); }); + +MOZ_GTEST_BENCH_F(BenchCollections, MozHash, + [this] { BenchImpl(Bench_Cpp_MozHashSet); }); + +MOZ_GTEST_BENCH_F(BenchCollections, RustHash, + [this] { BenchImpl(Bench_Rust_HashSet); }); + +MOZ_GTEST_BENCH_F(BenchCollections, RustFnvHash, + [this] { BenchImpl(Bench_Rust_FnvHashSet); }); + +MOZ_GTEST_BENCH_F(BenchCollections, RustFxHash, + [this] { BenchImpl(Bench_Rust_FxHashSet); }); |