src/tint/utils/containers/hashset_bench.cc

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#include <cstddef>
#include <cstdint>
#include <vector>

#include "benchmark/benchmark.h"
#include "src/tint/utils/containers/hashset.h"
#include "src/tint/utils/memory/block_allocator.h"

namespace tint {
namespace {

constexpr size_t kNumNodes = 16384;

struct alignas(16) BenchNode {
    uint64_t payload[8] = {};
};
static_assert(sizeof(BenchNode) == 64);

void HashsetPointerBlockAllocator(::benchmark::State& state) {
    BlockAllocator<BenchNode> allocator;
    std::vector<const BenchNode*> ptrs;
    ptrs.reserve(kNumNodes);
    for (size_t i = 0; i < kNumNodes; i++) {
        ptrs.push_back(allocator.Create());
    }

    for (auto _ : state) {
        Hashset<const BenchNode*, 8> set;
        for (const auto* ptr : ptrs) {
            set.Add(ptr);
        }
        size_t found = 0;
        for (const auto* ptr : ptrs) {
            if (set.Contains(ptr)) {
                found++;
            }
        }
        ::benchmark::DoNotOptimize(found);
    }
}
BENCHMARK(HashsetPointerBlockAllocator);

void HashsetPointerHighBitSaturation(::benchmark::State& state) {
    constexpr uintptr_t kBaseAddress = (sizeof(uintptr_t) > 4)
                                           ? static_cast<uintptr_t>(0x00007fff00000000ULL)
                                           : static_cast<uintptr_t>(0x7fff0000U);
    std::vector<const BenchNode*> ptrs;
    ptrs.reserve(kNumNodes);
    for (size_t i = 0; i < kNumNodes; i++) {
        // Hashset only hashes and compares pointer values without dereferencing them.
        ptrs.push_back(reinterpret_cast<const BenchNode*>(kBaseAddress + i * sizeof(BenchNode)));
    }

    for (auto _ : state) {
        Hashset<const BenchNode*, 8> set;
        for (const auto* ptr : ptrs) {
            set.Add(ptr);
        }
        size_t found = 0;
        for (const auto* ptr : ptrs) {
            if (set.Contains(ptr)) {
                found++;
            }
        }
        ::benchmark::DoNotOptimize(found);
    }
}
BENCHMARK(HashsetPointerHighBitSaturation);

}  // namespace
}  // namespace tint