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Add snappy::CompressFromIOVec.

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This reads from an `iovec` array rather than from a `char` array as in `snappy::Compress`.

PiperOrigin-RevId: 476930623
This commit is contained in:
Matt Callanan
2022-09-26 10:23:33 -07:00
committed by Victor Costan
parent af720f9a3b
commit 9758c9dfd7
4 changed files with 218 additions and 23 deletions
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52
snappy_benchmark.cc
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@@ -149,7 +149,55 @@ void BM_UValidateMedley(benchmark::State& state) {
}
BENCHMARK(BM_UValidateMedley);
void BM_UIOVec(benchmark::State& state) {
void BM_UIOVecSource(benchmark::State& state) {
// Pick file to process based on state.range(0).
int file_index = state.range(0);
CHECK_GE(file_index, 0);
CHECK_LT(file_index, ARRAYSIZE(kTestDataFiles));
std::string contents =
ReadTestDataFile(kTestDataFiles[file_index].filename,
kTestDataFiles[file_index].size_limit);
// Create `iovec`s of the `contents`.
const int kNumEntries = 10;
struct iovec iov[kNumEntries];
size_t used_so_far = 0;
for (int i = 0; i < kNumEntries; ++i) {
iov[i].iov_base = contents.data() + used_so_far;
if (used_so_far == contents.size()) {
iov[i].iov_len = 0;
continue;
}
if (i == kNumEntries - 1) {
iov[i].iov_len = contents.size() - used_so_far;
} else {
iov[i].iov_len = contents.size() / kNumEntries;
}
used_so_far += iov[i].iov_len;
}
char* dst = new char[snappy::MaxCompressedLength(contents.size())];
size_t zsize = 0;
for (auto s : state) {
snappy::RawCompressFromIOVec(iov, contents.size(), dst, &zsize);
benchmark::DoNotOptimize(iov);
}
state.SetBytesProcessed(static_cast<int64_t>(state.iterations()) *
static_cast<int64_t>(contents.size()));
const double compression_ratio =
static_cast<double>(zsize) / std::max<size_t>(1, contents.size());
state.SetLabel(StrFormat("%s (%.2f %%)", kTestDataFiles[file_index].label,
100.0 * compression_ratio));
VLOG(0) << StrFormat("compression for %s: %d -> %d bytes",
kTestDataFiles[file_index].label, contents.size(),
zsize);
delete[] dst;
}
BENCHMARK(BM_UIOVecSource)->DenseRange(0, ARRAYSIZE(kTestDataFiles) - 1);
void BM_UIOVecSink(benchmark::State& state) {
// Pick file to process based on state.range(0).
int file_index = state.range(0);
@@ -193,7 +241,7 @@ void BM_UIOVec(benchmark::State& state) {
delete[] dst;
}
BENCHMARK(BM_UIOVec)->DenseRange(0, 4);
BENCHMARK(BM_UIOVecSink)->DenseRange(0, 4);
void BM_UFlatSink(benchmark::State& state) {
// Pick file to process based on state.range(0).