disk_cache_perftest.cc

// Copyright (c) 2011 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include <limits>
#include <string>

#include "base/barrier_closure.h"
#include "base/bind.h"
#include "base/bind_helpers.h"
#include "base/files/file_enumerator.h"
#include "base/files/file_path.h"
#include "base/hash.h"
#include "base/process/process_metrics.h"
#include "base/rand_util.h"
#include "base/run_loop.h"
#include "base/strings/string_number_conversions.h"
#include "base/strings/string_util.h"
#include "base/test/perf_time_logger.h"
#include "base/test/scoped_task_environment.h"
#include "base/test/test_file_util.h"
#include "base/threading/thread.h"
#include "net/base/cache_type.h"
#include "net/base/io_buffer.h"
#include "net/base/net_errors.h"
#include "net/base/test_completion_callback.h"
#include "net/disk_cache/backend_cleanup_tracker.h"
#include "net/disk_cache/blockfile/backend_impl.h"
#include "net/disk_cache/blockfile/block_files.h"
#include "net/disk_cache/disk_cache.h"
#include "net/disk_cache/disk_cache_test_base.h"
#include "net/disk_cache/disk_cache_test_util.h"
#include "net/disk_cache/simple/simple_backend_impl.h"
#include "net/disk_cache/simple/simple_index.h"
#include "net/disk_cache/simple/simple_index_file.h"
#include "testing/gtest/include/gtest/gtest.h"
#include "testing/platform_test.h"

using base::Time;

namespace {

void MaybeSetFdLimit(unsigned int max_descriptors) {
#if defined(OS_POSIX)
  base::SetFdLimit(max_descriptors);
#endif
}

struct TestEntry {
  std::string key;
  int data_len;
};

class DiskCachePerfTest : public DiskCacheTestWithCache {
 public:
  DiskCachePerfTest()
      : DiskCacheTestWithCache(&scoped_task_environment_),
        saved_fd_limit_(base::GetMaxFds()) {
    if (saved_fd_limit_ < kFdLimitForCacheTests)
      MaybeSetFdLimit(kFdLimitForCacheTests);
  }

  ~DiskCachePerfTest() override {
    if (saved_fd_limit_ < kFdLimitForCacheTests)
      MaybeSetFdLimit(saved_fd_limit_);
  }

 protected:
  enum class WhatToRead {
    HEADERS_ONLY,
    HEADERS_AND_BODY,
  };

  // Helper methods for constructing tests.
  bool TimeWrite();
  bool TimeRead(WhatToRead what_to_read, const char* timer_message);
  void ResetAndEvictSystemDiskCache();

  // Complete perf tests.
  void CacheBackendPerformance();

  const size_t kFdLimitForCacheTests = 8192;

  const int kNumEntries = 1000;
  const int kHeadersSize = 800;
  const int kBodySize = 256 * 1024 - 1;

  std::vector<TestEntry> entries_;

 private:
  const size_t saved_fd_limit_;
  base::test::ScopedTaskEnvironment scoped_task_environment_;
};

// Creates num_entries on the cache, and writes kHeaderSize bytes of metadata
// and up to kBodySize of data to each entry.
bool DiskCachePerfTest::TimeWrite() {
  // TODO(gavinp): This test would be significantly more realistic if it didn't
  // do single reads and writes. Perhaps entries should be written 64kb at a
  // time. As well, not all entries should be created and written essentially
  // simultaneously; some number of entries in flight at a time would be a
  // likely better testing load.
  scoped_refptr<net::IOBuffer> buffer1(new net::IOBuffer(kHeadersSize));
  scoped_refptr<net::IOBuffer> buffer2(new net::IOBuffer(kBodySize));

  CacheTestFillBuffer(buffer1->data(), kHeadersSize, false);
  CacheTestFillBuffer(buffer2->data(), kBodySize, false);

  int expected = 0;

  MessageLoopHelper helper;
  CallbackTest callback(&helper, true);

  base::PerfTimeLogger timer("Write disk cache entries");

  for (int i = 0; i < kNumEntries; i++) {
    TestEntry entry;
    entry.key = GenerateKey(true);
    entry.data_len = base::RandInt(0, kBodySize);
    entries_.push_back(entry);

    disk_cache::Entry* cache_entry;
    net::TestCompletionCallback cb;
    int rv = cache_->CreateEntry(entry.key, &cache_entry, cb.callback());
    if (net::OK != cb.GetResult(rv))
      break;
    int ret = cache_entry->WriteData(
        0, 0, buffer1.get(), kHeadersSize,
        base::Bind(&CallbackTest::Run, base::Unretained(&callback)), false);
    if (net::ERR_IO_PENDING == ret)
      expected++;
    else if (kHeadersSize != ret)
      break;

    ret = cache_entry->WriteData(
        1, 0, buffer2.get(), entry.data_len,
        base::Bind(&CallbackTest::Run, base::Unretained(&callback)), false);
    if (net::ERR_IO_PENDING == ret)
      expected++;
    else if (entry.data_len != ret)
      break;
    cache_entry->Close();
  }

  helper.WaitUntilCacheIoFinished(expected);
  timer.Done();

  return expected == helper.callbacks_called();
}

// Reads the data and metadata from each entry listed on |entries|.
bool DiskCachePerfTest::TimeRead(WhatToRead what_to_read,
                                 const char* timer_message) {
  scoped_refptr<net::IOBuffer> buffer1(new net::IOBuffer(kHeadersSize));
  scoped_refptr<net::IOBuffer> buffer2(new net::IOBuffer(kBodySize));

  CacheTestFillBuffer(buffer1->data(), kHeadersSize, false);
  CacheTestFillBuffer(buffer2->data(), kBodySize, false);

  int expected = 0;

  MessageLoopHelper helper;
  CallbackTest callback(&helper, true);

  base::PerfTimeLogger timer(timer_message);

  for (int i = 0; i < kNumEntries; i++) {
    disk_cache::Entry* cache_entry;
    net::TestCompletionCallback cb;
    int rv = cache_->OpenEntry(entries_[i].key, &cache_entry, cb.callback());
    if (net::OK != cb.GetResult(rv))
      break;
    int ret = cache_entry->ReadData(
        0, 0, buffer1.get(), kHeadersSize,
        base::Bind(&CallbackTest::Run, base::Unretained(&callback)));
    if (net::ERR_IO_PENDING == ret)
      expected++;
    else if (kHeadersSize != ret)
      break;

    if (what_to_read == WhatToRead::HEADERS_AND_BODY) {
      ret = cache_entry->ReadData(
          1, 0, buffer2.get(), entries_[i].data_len,
          base::Bind(&CallbackTest::Run, base::Unretained(&callback)));
      if (net::ERR_IO_PENDING == ret)
        expected++;
      else if (entries_[i].data_len != ret)
        break;
    }

    cache_entry->Close();
  }

  helper.WaitUntilCacheIoFinished(expected);
  timer.Done();

  return (expected == helper.callbacks_called());
}

TEST_F(DiskCachePerfTest, BlockfileHashes) {
  base::PerfTimeLogger timer("Hash disk cache keys");
  for (int i = 0; i < 300000; i++) {
    std::string key = GenerateKey(true);
    base::Hash(key);
  }
  timer.Done();
}

void DiskCachePerfTest::ResetAndEvictSystemDiskCache() {
  base::RunLoop().RunUntilIdle();
  cache_.reset();

  // Flush all files in the cache out of system memory.
  const base::FilePath::StringType file_pattern = FILE_PATH_LITERAL("*");
  base::FileEnumerator enumerator(cache_path_, true /* recursive */,
                                  base::FileEnumerator::FILES, file_pattern);
  for (base::FilePath file_path = enumerator.Next(); !file_path.empty();
       file_path = enumerator.Next()) {
    ASSERT_TRUE(base::EvictFileFromSystemCache(file_path));
  }
#if defined(OS_LINUX) || defined(OS_ANDROID)
  // And, cache directories, on platforms where the eviction utility supports
  // this (currently Linux and Android only).
  if (simple_cache_mode_) {
    ASSERT_TRUE(
        base::EvictFileFromSystemCache(cache_path_.AppendASCII("index-dir")));
  }
  ASSERT_TRUE(base::EvictFileFromSystemCache(cache_path_));
#endif

  DisableFirstCleanup();
  InitCache();
}

void DiskCachePerfTest::CacheBackendPerformance() {
  InitCache();
  EXPECT_TRUE(TimeWrite());

  disk_cache::SimpleBackendImpl::FlushWorkerPoolForTesting();
  base::RunLoop().RunUntilIdle();

  ResetAndEvictSystemDiskCache();
  EXPECT_TRUE(TimeRead(WhatToRead::HEADERS_ONLY,
                       "Read disk cache headers only (cold)"));
  EXPECT_TRUE(TimeRead(WhatToRead::HEADERS_ONLY,
                       "Read disk cache headers only (warm)"));

  disk_cache::SimpleBackendImpl::FlushWorkerPoolForTesting();
  base::RunLoop().RunUntilIdle();

  ResetAndEvictSystemDiskCache();
  EXPECT_TRUE(
      TimeRead(WhatToRead::HEADERS_AND_BODY, "Read disk cache entries (cold)"));
  EXPECT_TRUE(
      TimeRead(WhatToRead::HEADERS_AND_BODY, "Read disk cache entries (warm)"));

  disk_cache::SimpleBackendImpl::FlushWorkerPoolForTesting();
  base::RunLoop().RunUntilIdle();
}

TEST_F(DiskCachePerfTest, CacheBackendPerformance) {
  CacheBackendPerformance();
}

TEST_F(DiskCachePerfTest, SimpleCacheBackendPerformance) {
  SetSimpleCacheMode();
  CacheBackendPerformance();
}

// Creating and deleting "entries" on a block-file is something quite frequent
// (after all, almost everything is stored on block files). The operation is
// almost free when the file is empty, but can be expensive if the file gets
// fragmented, or if we have multiple files. This test measures that scenario,
// by using multiple, highly fragmented files.
TEST_F(DiskCachePerfTest, BlockFilesPerformance) {
  ASSERT_TRUE(CleanupCacheDir());

  disk_cache::BlockFiles files(cache_path_);
  ASSERT_TRUE(files.Init(true));

  const int kNumBlocks = 60000;
  disk_cache::Addr address[kNumBlocks];

  base::PerfTimeLogger timer1("Fill three block-files");

  // Fill up the 32-byte block file (use three files).
  for (int i = 0; i < kNumBlocks; i++) {
    int block_size = base::RandInt(1, 4);
    EXPECT_TRUE(
        files.CreateBlock(disk_cache::RANKINGS, block_size, &address[i]));
  }

  timer1.Done();
  base::PerfTimeLogger timer2("Create and delete blocks");

  for (int i = 0; i < 200000; i++) {
    int block_size = base::RandInt(1, 4);
    int entry = base::RandInt(0, kNumBlocks - 1);

    files.DeleteBlock(address[entry], false);
    EXPECT_TRUE(
        files.CreateBlock(disk_cache::RANKINGS, block_size, &address[entry]));
  }

  timer2.Done();
  base::RunLoop().RunUntilIdle();
}

void VerifyRvAndCallClosure(base::Closure* c, int expect_rv, int rv) {
  EXPECT_EQ(expect_rv, rv);
  c->Run();
}

TEST_F(DiskCachePerfTest, SimpleCacheInitialReadPortion) {
  // A benchmark that aims to measure how much time we take in I/O thread
  // for initial bookkeeping before returning to the caller, and how much
  // after (batched up some). The later portion includes some event loop
  // overhead.
  const int kBatchSize = 100;

  SetSimpleCacheMode();

  InitCache();
  // Write out the entries, and keep their objects around.
  scoped_refptr<net::IOBuffer> buffer1(new net::IOBuffer(kHeadersSize));
  scoped_refptr<net::IOBuffer> buffer2(new net::IOBuffer(kBodySize));

  CacheTestFillBuffer(buffer1->data(), kHeadersSize, false);
  CacheTestFillBuffer(buffer2->data(), kBodySize, false);

  disk_cache::Entry* cache_entry[kBatchSize];
  for (int i = 0; i < kBatchSize; ++i) {
    net::TestCompletionCallback cb;
    int rv = cache_->CreateEntry(base::IntToString(i), &cache_entry[i],
                                 cb.callback());
    ASSERT_EQ(net::OK, cb.GetResult(rv));

    rv = cache_entry[i]->WriteData(0, 0, buffer1.get(), kHeadersSize,
                                   cb.callback(), false);
    ASSERT_EQ(kHeadersSize, cb.GetResult(rv));
    rv = cache_entry[i]->WriteData(1, 0, buffer2.get(), kBodySize,
                                   cb.callback(), false);
    ASSERT_EQ(kBodySize, cb.GetResult(rv));
  }

  // Now repeatedly read these, batching up the waiting to try to
  // account for the two portions separately. Note that we need separate entries
  // since we are trying to keep interesting work from being on the delayed-done
  // portion.
  const int kIterations = 50000;

  double elapsed_early = 0.0;
  double elapsed_late = 0.0;

  for (int i = 0; i < kIterations; ++i) {
    base::RunLoop event_loop;
    base::Closure barrier =
        base::BarrierClosure(kBatchSize, event_loop.QuitWhenIdleClosure());
    net::CompletionCallback cb_batch(base::Bind(
        VerifyRvAndCallClosure, base::Unretained(&barrier), kHeadersSize));

    base::ElapsedTimer timer_early;
    for (int e = 0; e < kBatchSize; ++e) {
      int rv =
          cache_entry[e]->ReadData(0, 0, buffer1.get(), kHeadersSize, cb_batch);
      if (rv != net::ERR_IO_PENDING) {
        barrier.Run();
        ASSERT_EQ(kHeadersSize, rv);
      }
    }
    elapsed_early += timer_early.Elapsed().InMillisecondsF();

    base::ElapsedTimer timer_late;
    event_loop.Run();
    elapsed_late += timer_late.Elapsed().InMillisecondsF();
  }

  // Cleanup
  for (int i = 0; i < kBatchSize; ++i)
    cache_entry[i]->Close();

  disk_cache::SimpleBackendImpl::FlushWorkerPoolForTesting();
  base::RunLoop().RunUntilIdle();
  LOG(ERROR) << "Early portion:" << elapsed_early << " ms";
  LOG(ERROR) << "\tPer entry:"
             << 1000 * (elapsed_early / (kIterations * kBatchSize)) << " us";
  LOG(ERROR) << "Event loop portion: " << elapsed_late << " ms";
  LOG(ERROR) << "\tPer entry:"
             << 1000 * (elapsed_late / (kIterations * kBatchSize)) << " us";
}

// Measures how quickly SimpleIndex can compute which entries to evict.
TEST(SimpleIndexPerfTest, EvictionPerformance) {
  const int kEntries = 10000;

  class NoOpDelegate : public disk_cache::SimpleIndexDelegate {
    void DoomEntries(std::vector<uint64_t>* entry_hashes,
                     const net::CompletionCallback& callback) override {}
  };

  NoOpDelegate delegate;
  base::Time start(base::Time::Now());

  double evict_elapsed_ms = 0;
  int iterations = 0;
  while (iterations < 61000) {
    ++iterations;
    disk_cache::SimpleIndex index(/* io_thread = */ nullptr,
                                  /* cleanup_tracker = */ nullptr, &delegate,
                                  net::DISK_CACHE,
                                  /* simple_index_file = */ nullptr);

    // Make sure large enough to not evict on insertion.
    index.SetMaxSize(kEntries * 2);

    for (int i = 0; i < kEntries; ++i) {
      index.InsertEntryForTesting(
          i, disk_cache::EntryMetadata(start + base::TimeDelta::FromSeconds(i),
                                       1u));
    }

    // Trigger an eviction.
    base::ElapsedTimer timer;
    index.SetMaxSize(kEntries);
    index.UpdateEntrySize(0, 1u);
    evict_elapsed_ms += timer.Elapsed().InMillisecondsF();
  }

  LOG(ERROR) << "Average time to evict:" << (evict_elapsed_ms / iterations)
             << "ms";
}

}  // namespace