daScript/examples/hash/bench_hash_insert_only.cpp at master · WhyNot135/daScript · GitHub

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// Find x10 only — compares daslang_hash_{map,set} vs daslang_insert_only_hash_{map,set}.

// Both use the same hash, same load factor, same layout (parallel hashes/keys/values

// vectors). The insert-only variant drops erase + tombstone tracking. Since no erases

// happen in the bench, the tables end up structurally identical — this measures the

// inherent cost of carrying the erase machinery (one extra branch in reserve_slot, one

// extra `<= HASH_KILLED` in iterator skip; find_index is identical between the two).

// Likely outcome: small delta, dominated by noise. The bench answers "by how much?".

// Build: cmake --build build/example_hash_bench --config Release --target example_hash_insert_only_bench

// Run: build/example_hash_bench/Release/example_hash_insert_only_bench.exe

#include <daScript/das_config.h>

#include <chrono>

#include <cstdint>

#include <cstdio>

#include <cstdlib>

#include <cstring>

#include <random>

#include <string>

#include <unordered_set>

#include <utility>

#include <vector>

namespace das { void das_throw(const char * msg); }

void das::das_throw(const char * msg) {

std::fprintf(stderr, "%s\n", msg); std::abort();

}

namespace {

constexpr uint32_t SEED = 0xC0FFEEu;

constexpr size_t SIZES[] = { 1000, 10000, 100000 };

constexpr size_t MAX_N = 100000;

constexpr int FIND_MULT = 10;

volatile size_t g_sink = 0;

int pick_iters_find (size_t n) {

if (n <= 1000) return 500;

if (n <= 10000) return 50;

return 5;

}

struct CStrEq {

bool operator () (const char * a, const char * b) const noexcept { return std::strcmp(a, b) == 0; }

};

struct CStrHash {

size_t operator () (const char * s) const noexcept {

uint64_t h = 14695981039346656037ull;

for (; *s; ++s) { h ^= uint8_t(*s); h *= 1099511628211ull; }

return size_t(h);

}

};

// Map traits — pick (Regular, InsertOnly) per key type

template <typename K>

struct MapTraits {

using Reg = das::daslang_hash_map<K, void*>;

using IO = das::daslang_insert_only_hash_map<K, void*>;

};

template <>

struct MapTraits<const char*> {

using Reg = das::daslang_hash_map<const char*, void*, CStrHash, CStrEq>;

using IO = das::daslang_insert_only_hash_map<const char*, void*, CStrHash, CStrEq>;

};

template <typename K>

struct SetTraits {

using Reg = das::daslang_hash_set<K>;

using IO = das::daslang_insert_only_hash_set<K>;

};

template <>

struct SetTraits<const char*> {

using Reg = das::daslang_hash_set<const char*, CStrHash, CStrEq>;

using IO = das::daslang_insert_only_hash_set<const char*, CStrHash, CStrEq>;

};

// ===== Corpora (same generator as the other benches) =====

struct StringCorpus {

std::vector<std::string> strs;

std::vector<const char*> cstrs;

std::vector<uint64_t> hashes;

};

StringCorpus make_string_corpus (size_t n, uint32_t seed) {

static const char alpha[] = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789_";

constexpr int ALPHA_N = sizeof(alpha) - 1;

std::mt19937 rng(seed);

std::normal_distribution<float> len_dist(10.0f, 4.0f);

StringCorpus c;

c.strs.reserve(n); c.cstrs.reserve(n); c.hashes.reserve(n);

std::unordered_set<std::string> seen; seen.reserve(n);

while (c.strs.size() < n) {

int len = int(len_dist(rng));

if (len < 4) len = 4;

if (len > 20) len = 20;

std::string s; s.resize(size_t(len));

for (int i = 0; i < len; ++i) s[i] = alpha[rng() % ALPHA_N];

if (seen.insert(s).second) c.strs.push_back(std::move(s));

}

das::daslang_hash<das::string> h{};

for (const auto & s : c.strs) {

c.cstrs.push_back(s.c_str());

c.hashes.push_back(uint64_t(h(s)));

}

return c;

}

struct PtrPool {

std::vector<void*> ptrs;

size_t block_size = 0;

PtrPool () = default;

~PtrPool () { for (auto p : ptrs) std::free(p); }

PtrPool (const PtrPool &) = delete;

PtrPool & operator = (const PtrPool &) = delete;

PtrPool (PtrPool && o) noexcept : ptrs(std::move(o.ptrs)), block_size(o.block_size) {}

};

PtrPool make_ptr_pool (size_t n, size_t block_size) {

PtrPool p; p.block_size = block_size; p.ptrs.reserve(n);

for (size_t i = 0; i < n; ++i) p.ptrs.push_back(std::malloc(block_size));

return p;

}

template <typename K>

std::vector<K> make_find_queries (const std::vector<K> & keys, uint32_t seed) {

std::mt19937 rng(seed);

std::vector<K> q; q.reserve(keys.size() * size_t(FIND_MULT));

std::uniform_int_distribution<size_t> pick(0, keys.size() - 1);

for (size_t i = 0; i < keys.size() * size_t(FIND_MULT); ++i) q.push_back(keys[pick(rng)]);

return q;

}

// ===== Map find bench =====

template <typename Map>

double bench_find_map (const std::vector<typename Map::key_type> & keys,

const std::vector<typename Map::key_type> & queries,

int iters, const char * label) {

Map m;

for (const auto & k : keys) m.emplace(k, (void*)nullptr);

if (m.size() != keys.size()) {

std::fprintf(stderr, "FAIL [%s map pre-build]: size %zu != %zu\n", label, m.size(), keys.size());

std::abort();

}

{

size_t hits = 0;

for (const auto & q : queries) hits += (m.find(q) != m.end()) ? 1 : 0;

if (hits != queries.size()) {

std::fprintf(stderr, "FAIL [%s map verify]: hits %zu != %zu\n", label, hits, queries.size());

std::abort();

}

using clk = std::chrono::steady_clock;

auto t0 = clk::now();

size_t hits = 0;

for (int i = 0; i < iters; ++i)

for (const auto & q : queries) hits += (m.find(q) != m.end()) ? 1 : 0;

auto t1 = clk::now();

g_sink ^= hits;

return double(std::chrono::duration_cast<std::chrono::nanoseconds>(t1 - t0).count()) / iters;

}

template <typename Set>

double bench_find_set (const std::vector<typename Set::key_type> & keys,

const std::vector<typename Set::key_type> & queries,

int iters, const char * label) {

Set s;

for (const auto & k : keys) s.insert(k);

if (s.size() != keys.size()) {

std::fprintf(stderr, "FAIL [%s set pre-build]: size %zu != %zu\n", label, s.size(), keys.size());

std::abort();

}

{

size_t hits = 0;

for (const auto & q : queries) hits += (s.find(q) != s.end()) ? 1 : 0;

if (hits != queries.size()) {

std::fprintf(stderr, "FAIL [%s set verify]: hits %zu != %zu\n", label, hits, queries.size());

std::abort();

}

using clk = std::chrono::steady_clock;

auto t0 = clk::now();

size_t hits = 0;

for (int i = 0; i < iters; ++i)

for (const auto & q : queries) hits += (s.find(q) != s.end()) ? 1 : 0;

auto t1 = clk::now();

g_sink ^= hits;

return double(std::chrono::duration_cast<std::chrono::nanoseconds>(t1 - t0).count()) / iters;

}

template <typename K>

void run_map_rows (const char * title, const std::vector<K> & full_keys) {

using T = MapTraits<K>;

std::printf("\n## %s\n\n", title);

std::printf("|--------|---------------:|-----------------:|--------:|\n");

for (size_t n : SIZES) {

if (n > full_keys.size()) continue;

std::vector<K> keys(full_keys.begin(), full_keys.begin() + n);

const int it = pick_iters_find(n);

auto queries = make_find_queries(keys, SEED + uint32_t(n));

double reg = bench_find_map<typename T::Reg>(keys, queries, it, "regular");

double io = bench_find_map<typename T::IO> (keys, queries, it, "insert-only");

std::printf("| %-6zu | %14.0f | %16.0f | %7.3f |\n", n, reg, io, io / reg);

}

std::fflush(stdout);

}

template <typename K>

void run_set_rows (const char * title, const std::vector<K> & full_keys) {

using T = SetTraits<K>;

std::printf("\n## %s\n\n", title);

std::printf("|--------|---------------:|-----------------:|--------:|\n");

for (size_t n : SIZES) {

if (n > full_keys.size()) continue;

std::vector<K> keys(full_keys.begin(), full_keys.begin() + n);

const int it = pick_iters_find(n);

auto queries = make_find_queries(keys, SEED + uint32_t(n));

double reg = bench_find_set<typename T::Reg>(keys, queries, it, "regular");

double io = bench_find_set<typename T::IO> (keys, queries, it, "insert-only");

std::printf("| %-6zu | %14.0f | %16.0f | %7.3f |\n", n, reg, io, io / reg);

}

std::fflush(stdout);

}

} // anonymous

int main () {

std::printf("# daslang_hash_* vs daslang_insert_only_hash_* — find x10\n\n");

std::printf("Stdlib: ");

#if defined(_MSC_VER)

std::printf("MSVC stdlib (_MSC_VER=%d)\n", _MSC_VER);

#elif defined(__GLIBCXX__)

std::printf("libstdc++ %d\n", __GLIBCXX__);

#elif defined(_LIBCPP_VERSION)

std::printf("libc++ %d\n", _LIBCPP_VERSION);

#else

std::printf("unknown\n");

#endif

std::printf("Compiler: ");

#if defined(_MSC_VER)

std::printf("MSVC %d\n", _MSC_VER);

#elif defined(__clang__)

std::printf("clang %d.%d.%d\n", __clang_major__, __clang_minor__, __clang_patchlevel__);

#elif defined(__GNUC__)

std::printf("gcc %d.%d.%d\n", __GNUC__, __GNUC_MINOR__, __GNUC_PATCHLEVEL__);

#else

std::printf("unknown\n");

#endif

std::printf("\nNo erases happen in this bench, so both variants build structurally identical tables.\n");

std::printf("Find_index code is identical between regular and insert-only — the only differences\n");

std::printf("are iterator skip cost (irrelevant for find) and reserve_slot branch count (irrelevant\n");

std::printf("for find after the table is built). IO/reg ratio at ~1.0 = no meaningful difference.\n");

auto str_corpus = make_string_corpus(MAX_N, SEED);

auto ptr_pool_32 = make_ptr_pool(MAX_N, 32);

auto ptr_pool_128 = make_ptr_pool(MAX_N, 128);

run_map_rows<const char*>("Map<const char*, void*>", str_corpus.cstrs);

run_map_rows<std::string>("Map<std::string, void*>", str_corpus.strs);

run_map_rows<uint64_t> ("Map<uint64_t, void*>", str_corpus.hashes);

run_map_rows<void*> ("Map<void* (32B alloc), void*>", ptr_pool_32.ptrs);

run_map_rows<void*> ("Map<void* (128B alloc), void*>", ptr_pool_128.ptrs);

run_set_rows<const char*>("Set<const char*>", str_corpus.cstrs);

run_set_rows<std::string>("Set<std::string>", str_corpus.strs);

run_set_rows<uint64_t> ("Set<uint64_t>", str_corpus.hashes);

run_set_rows<void*> ("Set<void* (32B alloc)>", ptr_pool_32.ptrs);

run_set_rows<void*> ("Set<void* (128B alloc)>", ptr_pool_128.ptrs);

std::printf("\n(checksum: 0x%zx)\n", size_t(g_sink));

return 0;

}

daScript/examples/hash/bench_hash_insert_only.cpp at master · WhyNot135/daScript · GitHub

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