Windows-native sampling profiler wrapper class.

base/win/sampling_profiler_unittest.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 "base/win/sampling_profiler.h"
+
+#include "base/test/test_timeouts.h"
+#include "base/win/pe_image.h"
+#include "base/win/scoped_handle.h"
+#include "gtest/gtest.h"
+
+// The address of our image base.
+extern "C" IMAGE_DOS_HEADER __ImageBase;
+
+namespace base {
+namespace win {
+
+namespace {
+
+class SamplingProfilerTest : public testing::Test {
+ public:
+  SamplingProfilerTest() : code_start(NULL), code_size(0) {
+  }
+
+  virtual void SetUp() {
+    process.Set(::OpenProcess(PROCESS_QUERY_INFORMATION,
+                              FALSE,
+                              ::GetCurrentProcessId()));
+    ASSERT_TRUE(process.IsValid());
+
+    PEImage image(&__ImageBase);
+
+    // Get the address of the .text section, which is the first section output
+    // by the VS tools.
+    ASSERT_TRUE(image.GetNumSections() > 0);
+    const IMAGE_SECTION_HEADER* text_section = image.GetSectionHeader(0);
+    ASSERT_EQ(0, strncmp(".text",
+                         reinterpret_cast<const char*>(text_section->Name),
+                         arraysize(text_section->Name)));
+    ASSERT_NE(0U, text_section->Characteristics & IMAGE_SCN_MEM_EXECUTE);
+
+    code_start = reinterpret_cast<uint8*>(&__ImageBase) +
+        text_section->VirtualAddress;
+    code_size = text_section->Misc.VirtualSize;
+  }
+
+ protected:
+  ScopedHandle process;
+  void* code_start;
+  size_t code_size;
+};
+
+}  // namespace
+
+TEST_F(SamplingProfilerTest, Initialize) {
+  SamplingProfiler profiler;
+
+  ASSERT_TRUE(profiler.Initialize(process.Get(), code_start, code_size, 8));
+}
+
+TEST_F(SamplingProfilerTest, StartStop) {
+  SamplingProfiler profiler;
+
+  // Initialize with a huge bucket size, aiming for a single bucket.
+  ASSERT_TRUE(
+      profiler.Initialize(process.Get(), code_start, code_size, 31));
+
+  ASSERT_EQ(1, profiler.buckets().size());
+  ASSERT_EQ(0, profiler.buckets()[0]);
+
+  FILETIME ignore = {};
+  FILETIME user_time = {};
+  ASSERT_TRUE(::GetThreadTimes(
+      ::GetCurrentThread(), &ignore, &ignore, &ignore, &user_time));
+
+  base::Time start = base::Time::FromFileTime(user_time);
+  base::TimeDelta spin_time =
+      base::TimeDelta::FromMilliseconds(TestTimeouts::tiny_timeout_ms());
+
+  // Start the profiler.
+  ASSERT_TRUE(profiler.Start());
+
+  // Spin for spin_time CPU seconds to get some samples.
+  base::Time now;
+  do {
+    ASSERT_TRUE(::GetThreadTimes(
+        ::GetCurrentThread(), &ignore, &ignore, &ignore, &user_time));
+
+    now = base::Time::FromFileTime(user_time);
+  } while(now - start < spin_time);
+
+  // Stop the profiler.
+  ASSERT_TRUE(profiler.Stop());
+
+  // Check that we got some samples.
+  ASSERT_NE(0U, profiler.buckets()[0]);
+}
+
+TEST_F(SamplingProfilerTest, GetSetInterval) {
+  // Get the original sampling interval.
+  base::TimeDelta original_interval;
+  ASSERT_TRUE(SamplingProfiler::GetSamplingInterval(&original_interval));
+
+  // Set a new interval that's double the old one.
+  base::TimeDelta new_interval = original_interval * 2;
+  ASSERT_TRUE(SamplingProfiler::SetSamplingInterval(new_interval));
+
+  // And verify that we can fetch the new one.
+  base::TimeDelta set_interval;
+  ASSERT_TRUE(SamplingProfiler::GetSamplingInterval(&set_interval));
+  EXPECT_EQ(new_interval.InMicroseconds(), set_interval.InMicroseconds());
+
+  // Restore the original interval.
+  ASSERT_TRUE(SamplingProfiler::SetSamplingInterval(original_interval));
+}
+
+}  // namespace win
+}  // namespace base