[benchmark] Refactor io read measurement with pread
Test: atest MicrodroidBenchmarks
Change-Id: Ib14fab8e0e15c25c711d956b7f3226d42ad5b7bf
diff --git a/tests/benchmark/src/native/benchmarkbinary.cpp b/tests/benchmark/src/native/benchmarkbinary.cpp
index 18293f3..6321c25 100644
--- a/tests/benchmark/src/native/benchmarkbinary.cpp
+++ b/tests/benchmark/src/native/benchmarkbinary.cpp
@@ -94,11 +94,12 @@
Result<double> measure_read_rate(const std::string& filename, int64_t fileSizeBytes,
bool is_rand) {
const int64_t block_count = fileSizeBytes / kBlockSizeBytes;
- std::vector<uint64_t> offsets;
+ std::vector<uint64_t> offsets(block_count);
+ for (auto i = 0; i < block_count; ++i) {
+ offsets.push_back(i * kBlockSizeBytes);
+ }
if (is_rand) {
std::mt19937 rd{std::random_device{}()};
- offsets.reserve(block_count);
- for (auto i = 0; i < block_count; ++i) offsets.push_back(i * kBlockSizeBytes);
std::shuffle(offsets.begin(), offsets.end(), rd);
}
char buf[kBlockSizeBytes];
@@ -109,12 +110,7 @@
return ErrnoError() << "Read: opening " << filename << " failed";
}
for (auto i = 0; i < block_count; ++i) {
- if (is_rand) {
- if (lseek(fd.get(), offsets[i], SEEK_SET) == -1) {
- return ErrnoError() << "failed to lseek";
- }
- }
- auto bytes = read(fd.get(), buf, kBlockSizeBytes);
+ auto bytes = pread(fd, buf, kBlockSizeBytes, offsets[i]);
if (bytes == 0) {
return Error() << "unexpected end of file";
} else if (bytes == -1) {