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Implement multi-threaded BLAKE3 hashing

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silvanshade 2025-03-18 15:16:56 -06:00
parent b1783ff615
commit 7db388f597
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2 changed files with 23 additions and 2 deletions
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22
src/libutil/hash.cc
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@ -307,11 +307,31 @@ static void start(HashAlgorithm ha, Ctx & ctx)
else if (ha == HashAlgorithm::SHA512) SHA512_Init(&ctx.sha512); else if (ha == HashAlgorithm::SHA512) SHA512_Init(&ctx.sha512);
} }
// BLAKE3 data size threshold beyond which parallel hashing with TBB is likely faster.
//
// NOTE: This threshold is based on the recommended rule-of-thumb from the official BLAKE3 documentation for typical
// x86_64 hardware as of 2025. In the future it may make sense to allow the user to tune this through nix.conf.
const size_t blake3TbbThreshold = 128000;
// Decide which BLAKE3 update strategy to use based on some heuristics. Currently this just checks the data size but in
// the future it might also take into consideration available system resources or the presence of a shared-memory
// capable GPU for a heterogenous compute implementation.
void blake3_hasher_update_with_heuristics(blake3_hasher * blake3, std::string_view data)
{
#ifdef BLAKE3_USE_TBB
if (data.size() >= blake3TbbThreshold) {
blake3_hasher_update_tbb(blake3, data.data(), data.size());
} else
#endif
{
blake3_hasher_update(blake3, data.data(), data.size());
}
}
static void update(HashAlgorithm ha, Ctx & ctx, static void update(HashAlgorithm ha, Ctx & ctx,
std::string_view data) std::string_view data)
{ {
if (ha == HashAlgorithm::BLAKE3) blake3_hasher_update(&ctx.blake3, data.data(), data.size()); if (ha == HashAlgorithm::BLAKE3) blake3_hasher_update_with_heuristics(&ctx.blake3, data);
else if (ha == HashAlgorithm::MD5) MD5_Update(&ctx.md5, data.data(), data.size()); else if (ha == HashAlgorithm::MD5) MD5_Update(&ctx.md5, data.data(), data.size());
else if (ha == HashAlgorithm::SHA1) SHA1_Update(&ctx.sha1, data.data(), data.size()); else if (ha == HashAlgorithm::SHA1) SHA1_Update(&ctx.sha1, data.data(), data.size());
else if (ha == HashAlgorithm::SHA256) SHA256_Update(&ctx.sha256, data.data(), data.size()); else if (ha == HashAlgorithm::SHA256) SHA256_Update(&ctx.sha256, data.data(), data.size());

3
src/libutil/meson.build
View file

@ -50,7 +50,8 @@ endif
blake3 = dependency( blake3 = dependency(
'libblake3', 'libblake3',
version: '>= 1.5.5', version: '>= 1.8.2',
method : 'pkg-config',
) )
deps_private += blake3 deps_private += blake3