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// Copyright 2020 The gVisor Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include <fcntl.h>
#include <stdlib.h>
#include <sys/stat.h>
#include <sys/uio.h>
#include <unistd.h>
#include "gtest/gtest.h"
#include "benchmark/benchmark.h"
#include "test/util/file_descriptor.h"
#include "test/util/logging.h"
#include "test/util/temp_path.h"
#include "test/util/test_util.h"
namespace gvisor {
namespace testing {
namespace {
// Create a 1GB file that will be read from at random positions. This should
// invalid any performance gains from caching.
const uint64_t kFileSize = 1ULL << 30;
// How many bytes to write at once to initialize the file used to read from.
const uint32_t kWriteSize = 65536;
// Largest benchmarked read unit.
const uint32_t kMaxRead = 1UL << 26;
TempPath CreateFile(uint64_t file_size) {
auto path = TempPath::CreateFile().ValueOrDie();
FileDescriptor fd = Open(path.path(), O_WRONLY).ValueOrDie();
// Try to minimize syscalls by using maximum size writev() requests.
std::vector<char> buffer(kWriteSize);
RandomizeBuffer(buffer.data(), buffer.size());
const std::vector<std::vector<struct iovec>> iovecs_list =
GenerateIovecs(file_size, buffer.data(), buffer.size());
for (const auto& iovecs : iovecs_list) {
TEST_CHECK(writev(fd.get(), iovecs.data(), iovecs.size()) >= 0);
}
return path;
}
// Global test state, initialized once per process lifetime.
struct GlobalState {
const TempPath tmpfile;
explicit GlobalState(TempPath tfile) : tmpfile(std::move(tfile)) {}
};
GlobalState& GetGlobalState() {
// This gets created only once throughout the lifetime of the process.
// Use a dynamically allocated object (that is never deleted) to avoid order
// of destruction of static storage variables issues.
static GlobalState* const state =
// The actual file size is the maximum random seek range (kFileSize) + the
// maximum read size so we can read that number of bytes at the end of the
// file.
new GlobalState(CreateFile(kFileSize + kMaxRead));
return *state;
}
void BM_RandRead(benchmark::State& state) {
const int size = state.range(0);
GlobalState& global_state = GetGlobalState();
FileDescriptor fd =
ASSERT_NO_ERRNO_AND_VALUE(Open(global_state.tmpfile.path(), O_RDONLY));
std::vector<char> buf(size);
unsigned int seed = 1;
for (auto _ : state) {
TEST_CHECK(PreadFd(fd.get(), buf.data(), buf.size(),
rand_r(&seed) % (kFileSize - buf.size())) == size);
}
state.SetBytesProcessed(static_cast<int64_t>(size) *
static_cast<int64_t>(state.iterations()));
}
BENCHMARK(BM_RandRead)->Range(1, kMaxRead)->UseRealTime();
} // namespace
} // namespace testing
} // namespace gvisor
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