content/common/discardable_shared_memory_heap_perftest.cc

   1 // Copyright 2015 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "content/common/discardable_shared_memory_heap.h"
   6
   7 #include <algorithm>
   8 #include <cmath>
   9 #include <cstdlib>
  10
  11 #include "base/bind.h"
  12 #include "base/callback_helpers.h"
  13 #include "base/memory/discardable_shared_memory.h"
  14 #include "base/memory/scoped_vector.h"
  15 #include "base/process/process_metrics.h"
  16 #include "testing/gtest/include/gtest/gtest.h"
  17 #include "testing/perf/perf_test.h"
  18
  19 namespace content {
  20 namespace {
  21
  22 const int kTimeLimitMs = 2000;
  23 const int kTimeCheckInterval = 8192;
  24
  25 void NullTask() {
  26 }
  27
  28 TEST(DiscardableSharedMemoryHeapTest, SearchFreeLists) {
  29   size_t block_size = base::GetPageSize();
  30   DiscardableSharedMemoryHeap heap(block_size);
  31
  32   const size_t kBlocks = 4096;
  33   const size_t kSegments = 16;
  34   size_t segment_size = block_size * kBlocks;
  35
  36   for (size_t i = 0; i < kSegments; ++i) {
  37     scoped_ptr<base::DiscardableSharedMemory> memory(
  38         new base::DiscardableSharedMemory);
  39     ASSERT_TRUE(memory->CreateAndMap(segment_size));
  40     heap.MergeIntoFreeLists(
  41         heap.Grow(memory.Pass(), segment_size, base::Bind(NullTask)).Pass());
  42   }
  43
  44   unsigned kSeed = 1;
  45   // Use kSeed as seed for random number generator.
  46   srand(kSeed);
  47
  48   // Pre-compute random values.
  49   int random_span[kTimeCheckInterval];
  50   size_t random_blocks[kTimeCheckInterval];
  51   for (int i = 0; i < kTimeCheckInterval; ++i) {
  52     random_span[i] = std::rand();
  53     // Exponentially distributed block size.
  54     const double kLambda = 2.0;
  55     double v = static_cast<double>(std::rand()) / RAND_MAX;
  56     random_blocks[i] = 1 + log(1.0 - v) / -kLambda * kBlocks;
  57   }
  58
  59   ScopedVector<base::ScopedClosureRunner> spans;
  60
  61   base::TimeTicks start = base::TimeTicks::Now();
  62   base::TimeTicks end = start + base::TimeDelta::FromMilliseconds(kTimeLimitMs);
  63   base::TimeDelta accumulator;
  64   int count = 0;
  65   while (start < end) {
  66     for (int i = 0; i < kTimeCheckInterval; ++i) {
  67       // Search for a perfect fit if greater than kBlocks.
  68       size_t slack =
  69           random_blocks[i] < kBlocks ? kBlocks - random_blocks[i] : 0;
  70       scoped_ptr<DiscardableSharedMemoryHeap::Span> span =
  71           heap.SearchFreeLists(random_blocks[i], slack);
  72       if (span) {
  73         spans.push_back(new base::ScopedClosureRunner(
  74             base::Bind(&DiscardableSharedMemoryHeap::MergeIntoFreeLists,
  75                        base::Unretained(&heap), base::Passed(&span))));
  76       } else if (!spans.empty()) {
  77         // Merge a random span back into the free list.
  78         std::swap(spans[random_span[i] % spans.size()], spans.back());
  79         spans.pop_back();
  80       }
  81
  82       ++count;
  83     }
  84
  85     base::TimeTicks now = base::TimeTicks::Now();
  86     accumulator += now - start;
  87     start = now;
  88   }
  89
  90   spans.clear();
  91
  92   perf_test::PrintResult("search_free_list", "", "",
  93                          count / accumulator.InSecondsF(), "runs/s", true);
  94 }
  95
  96 }  // namespace
  97 }  // namespace content