Windows-native sampling profiler wrapper class.

Review URL: http://codereview.chromium.org/8803022

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@113473 0039d316-1c4b-4281-b951-d872f2087c98

3 files changed, 423 insertions, 0 deletions

diff --git a/base/win/sampling_profiler.cc b/base/win/sampling_profiler.cc
new file mode 100644
index 0000000..d1f6fbc
--- /dev/null
+++ b/base/win/sampling_profiler.cc
@@ -0,0 +1,233 @@
+// 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 <winternl.h>  // for NTSTATUS.
+
+#include "base/lazy_instance.h"
+
+// Copied from wdm.h in the WDK as we don't want to take
+// a dependency on the WDK.
+typedef enum _KPROFILE_SOURCE {
+    ProfileTime,
+    ProfileAlignmentFixup,
+    ProfileTotalIssues,
+    ProfilePipelineDry,
+    ProfileLoadInstructions,
+    ProfilePipelineFrozen,
+    ProfileBranchInstructions,
+    ProfileTotalNonissues,
+    ProfileDcacheMisses,
+    ProfileIcacheMisses,
+    ProfileCacheMisses,
+    ProfileBranchMispredictions,
+    ProfileStoreInstructions,
+    ProfileFpInstructions,
+    ProfileIntegerInstructions,
+    Profile2Issue,
+    Profile3Issue,
+    Profile4Issue,
+    ProfileSpecialInstructions,
+    ProfileTotalCycles,
+    ProfileIcacheIssues,
+    ProfileDcacheAccesses,
+    ProfileMemoryBarrierCycles,
+    ProfileLoadLinkedIssues,
+    ProfileMaximum
+} KPROFILE_SOURCE;
+
+
+namespace {
+
+// Signatures for the native functions we need to access the sampling profiler.
+typedef NTSTATUS (NTAPI *ZwSetIntervalProfileFunc)(ULONG, KPROFILE_SOURCE);
+typedef NTSTATUS (NTAPI *ZwQueryIntervalProfileFunc)(KPROFILE_SOURCE, PULONG);
+
+typedef NTSTATUS (NTAPI *ZwCreateProfileFunc)(PHANDLE profile,
+                                              HANDLE process,
+                                              PVOID code_start,
+                                              ULONG code_size,
+                                              ULONG eip_bucket_shift,
+                                              PULONG buckets,
+                                              ULONG buckets_byte_size,
+                                              KPROFILE_SOURCE source,
+                                              DWORD_PTR processor_mask);
+
+typedef NTSTATUS (NTAPI *ZwStartProfileFunc)(HANDLE);
+typedef NTSTATUS (NTAPI *ZwStopProfileFunc)(HANDLE);
+
+// This class is used to lazy-initialize pointers to the native
+// functions we need to access.
+class ProfilerFuncs {
+ public:
+  ProfilerFuncs();
+
+  ZwSetIntervalProfileFunc ZwSetIntervalProfile;
+  ZwQueryIntervalProfileFunc ZwQueryIntervalProfile;
+  ZwCreateProfileFunc ZwCreateProfile;
+  ZwStartProfileFunc ZwStartProfile;
+  ZwStopProfileFunc ZwStopProfile;
+
+  // True iff all of the function pointers above were successfully initialized.
+  bool initialized_;
+};
+
+ProfilerFuncs::ProfilerFuncs() : initialized_(false) {
+  HMODULE ntdll = ::GetModuleHandle(L"ntdll.dll");
+  if (ntdll != NULL) {
+    ZwSetIntervalProfile = reinterpret_cast<ZwSetIntervalProfileFunc>(
+        ::GetProcAddress(ntdll, "ZwSetIntervalProfile"));
+    ZwQueryIntervalProfile = reinterpret_cast<ZwQueryIntervalProfileFunc>(
+        ::GetProcAddress(ntdll, "ZwQueryIntervalProfile"));
+    ZwCreateProfile = reinterpret_cast<ZwCreateProfileFunc>(
+        ::GetProcAddress(ntdll, "ZwCreateProfile"));
+    ZwStartProfile = reinterpret_cast<ZwStartProfileFunc>(
+        ::GetProcAddress(ntdll, "ZwStartProfile"));
+    ZwStopProfile = reinterpret_cast<ZwStopProfileFunc>(
+        ::GetProcAddress(ntdll, "ZwStopProfile"));
+
+    if (ZwSetIntervalProfile &&
+        ZwQueryIntervalProfile &&
+        ZwCreateProfile &&
+        ZwStartProfile &&
+        ZwStopProfile) {
+      initialized_ = true;
+    }
+  }
+}
+
+base::LazyInstance<ProfilerFuncs, base::LeakyLazyInstanceTraits<ProfilerFuncs>>
+    funcs = LAZY_INSTANCE_INITIALIZER;
+
+}  // namespace
+
+
+namespace base {
+namespace win {
+
+SamplingProfiler::SamplingProfiler() : is_started_(false) {
+}
+
+SamplingProfiler::~SamplingProfiler() {
+  if (is_started_) {
+    CHECK(Stop()) <<
+        "Unable to stop sampling profiler, this will cause memory corruption.";
+  }
+}
+
+bool SamplingProfiler::Initialize(HANDLE process,
+                                  void* start,
+                                  size_t size,
+                                  size_t log2_bucket_size) {
+  // You only get to initialize each instance once.
+  DCHECK(!profile_handle_.IsValid());
+  DCHECK(!is_started_);
+  DCHECK(start != NULL);
+  DCHECK_NE(0U, size);
+  DCHECK_LE(2, log2_bucket_size);
+  DCHECK_GE(32, log2_bucket_size);
+
+  // Bail if the native functions weren't found.
+  if (!funcs.Get().initialized_)
+    return false;
+
+  size_t bucket_size = 1 << log2_bucket_size;
+  size_t num_buckets = (size + bucket_size - 1) / bucket_size;
+  DCHECK(num_buckets != 0);
+  buckets_.resize(num_buckets);
+
+  // Get our affinity mask for the call below.
+  DWORD_PTR process_affinity = 0;
+  DWORD_PTR system_affinity = 0;
+  if (!::GetProcessAffinityMask(process, &process_affinity, &system_affinity)) {
+    LOG(ERROR) << "Failed to get process affinity mask.";
+    return false;
+  }
+
+  HANDLE profile = NULL;
+  NTSTATUS status =
+      funcs.Get().ZwCreateProfile(&profile,
+                                  process,
+                                  start,
+                                  static_cast<ULONG>(size),
+                                  static_cast<ULONG>(log2_bucket_size),
+                                  &buckets_[0],
+                                  static_cast<ULONG>(
+                                      sizeof(buckets_[0]) * num_buckets),
+                                  ProfileTime,
+                                  process_affinity);
+
+  if (!NT_SUCCESS(status)) {
+    // Might as well deallocate the buckets.
+    buckets_.resize(0);
+    LOG(ERROR) << "Failed to create profile, error 0x" << std::hex << status;
+    return false;
+  }
+
+  DCHECK(profile != NULL);
+  profile_handle_.Set(profile);
+
+  return true;
+}
+
+bool SamplingProfiler::Start() {
+  DCHECK(profile_handle_.IsValid());
+  DCHECK(!is_started_);
+  DCHECK(funcs.Get().initialized_);
+
+  NTSTATUS status = funcs.Get().ZwStartProfile(profile_handle_.Get());
+  if (!NT_SUCCESS(status))
+    return false;
+
+  is_started_ = true;
+
+  return true;
+}
+
+bool SamplingProfiler::Stop() {
+  DCHECK(profile_handle_.IsValid());
+  DCHECK(is_started_);
+  DCHECK(funcs.Get().initialized_);
+
+  NTSTATUS status = funcs.Get().ZwStopProfile(profile_handle_.Get());
+  if (!NT_SUCCESS(status))
+    return false;
+  is_started_ = false;
+
+  return true;
+}
+
+bool SamplingProfiler::SetSamplingInterval(base::TimeDelta sampling_interval) {
+  if (!funcs.Get().initialized_)
+    return false;
+
+  // According to Nebbet, the sampling interval is in units of 100ns.
+  ULONG interval = sampling_interval.InMicroseconds() * 10;
+  NTSTATUS status = funcs.Get().ZwSetIntervalProfile(interval, ProfileTime);
+  if (!NT_SUCCESS(status))
+    return false;
+
+  return true;
+}
+
+bool SamplingProfiler::GetSamplingInterval(base::TimeDelta* sampling_interval) {
+  DCHECK(sampling_interval != NULL);
+
+  if (!funcs.Get().initialized_)
+    return false;
+
+  ULONG interval = 0;
+  NTSTATUS status = funcs.Get().ZwQueryIntervalProfile(ProfileTime, &interval);
+  if (!NT_SUCCESS(status))
+    return false;
+
+  // According to Nebbet, the sampling interval is in units of 100ns.
+  *sampling_interval = base::TimeDelta::FromMicroseconds(interval / 10);
+
+  return true;
+}
+
+}  // namespace win
+}  // namespace base
diff --git a/base/win/sampling_profiler.h b/base/win/sampling_profiler.h
new file mode 100644
index 0000000..bf1be8c
--- /dev/null
+++ b/base/win/sampling_profiler.h
@@ -0,0 +1,74 @@
+// 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.
+
+#ifndef BASE_WIN_SAMPLING_PROFILER_H_
+#define BASE_WIN_SAMPLING_PROFILER_H_
+#pragma once
+
+#include <vector>
+
+#include "base/basictypes.h"
+#include "base/time.h"
+#include "base/win/scoped_handle.h"
+
+namespace base {
+namespace win {
+
+// This class exposes the functionality of Window's built-in sampling profiler.
+// Each profiler instance covers a range of memory, and while the profiler is
+// running, its buckets will count the number of times the instruction counter
+// lands in the associated range of memory on a sample.
+// The sampling interval is settable, but the setting is system-wide.
+class BASE_EXPORT SamplingProfiler {
+ public:
+  // Create an uninitialized sampling profiler.
+  SamplingProfiler();
+  ~SamplingProfiler();
+
+  // Initializes the profiler to cover the memory range |start| through
+  // |start| + |size|, in the process |process_handle| with bucket size
+  // |2^log2_bucket_size|, |log2_bucket_size| must be in the range 2-31,
+  // for bucket sizes of 4 bytes to 2 gigabytes.
+  // The process handle must grant at least PROCESS_QUERY_INFORMATION.
+  // The memory range should be exectuable code, like e.g. the text segment
+  // of an exectuable (whether DLL or EXE).
+  // Returns true on success.
+  bool Initialize(HANDLE process_handle,
+                  void* start,
+                  size_t size,
+                  size_t log2_bucket_size);
+
+  // Start this profiler, which must be initialized and not started.
+  bool Start();
+  // Stop this profiler, which must be started.
+  bool Stop();
+
+  // Get and set the sampling interval.
+  // Note that this is a system-wide setting.
+  static bool SetSamplingInterval(base::TimeDelta sampling_interval);
+  static bool GetSamplingInterval(base::TimeDelta* sampling_interval);
+
+  // Accessors.
+  bool is_started() const { return is_started_; }
+
+  // It is safe to read the counts in the sampling buckets at any time.
+  // Note however that there's no guarantee that you'll read consistent counts
+  // until the profiler has been stopped, as the counts may be updating on other
+  // CPU cores.
+  const std::vector<ULONG>& buckets() const { return buckets_; }
+
+ private:
+  // Handle to the corresponding kernel object.
+  ScopedHandle profile_handle_;
+  // True iff this profiler is started.
+  bool is_started_;
+  std::vector<ULONG> buckets_;
+
+  DISALLOW_COPY_AND_ASSIGN(SamplingProfiler);
+};
+
+}  // namespace win
+}  // namespace base
+
+#endif  // BASE_WIN_SAMPLING_PROFILER_H_
diff --git a/base/win/sampling_profiler_unittest.cc b/base/win/sampling_profiler_unittest.cc
new file mode 100644
index 0000000..caa4c63
--- /dev/null
+++ b/base/win/sampling_profiler_unittest.cc
@@ -0,0 +1,116 @@
+// 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 "testing/gtest/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, Sample) {
+  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]);
+
+  // We use a roomy timeout to make sure this test is not flaky.
+  // On the buildbots, there may not be a whole lot of CPU time
+  // allotted to our process in this wall-clock time duration,
+  // and samples will only accrue while this thread is busy on
+  // a CPU core.
+  base::TimeDelta spin_time =
+      base::TimeDelta::FromMilliseconds(TestTimeouts::action_timeout_ms());
+
+  base::TimeDelta save_sampling_interval;
+  ASSERT_TRUE(SamplingProfiler::GetSamplingInterval(&save_sampling_interval));
+
+  // Sample every 0.5 millisecs.
+  ASSERT_TRUE(SamplingProfiler::SetSamplingInterval(
+      base::TimeDelta::FromMicroseconds(500)));
+
+  ASSERT_TRUE(SamplingProfiler::SetSamplingInterval(
+      base::TimeDelta::FromMicroseconds(500)));
+
+  // Start the profiler.
+  ASSERT_TRUE(profiler.Start());
+
+  // Get a volatile pointer to our bucket to make sure that the compiler
+  // doesn't optimize out the test in the loop that follows.
+  volatile const ULONG* bucket_ptr = &profiler.buckets()[0];
+
+  // Spin for spin_time wall-clock seconds, or until we get some samples.
+  // Note that sleeping isn't going to do us any good, the samples only
+  // accrue while we're executing code.
+  base::Time start = base::Time::Now();
+  base::TimeDelta elapsed;
+  do {
+    elapsed = base::Time::Now() - start;
+  } while((elapsed < spin_time) && *bucket_ptr == 0);
+
+  // Stop the profiler.
+  ASSERT_TRUE(profiler.Stop());
+
+  // Restore the sampling interval we found.
+  ASSERT_TRUE(SamplingProfiler::SetSamplingInterval(save_sampling_interval));
+
+  // Check that we got some samples.
+  ASSERT_NE(0U, profiler.buckets()[0]);
+}
+
+}  // namespace win
+}  // namespace base