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// Copyright (c) 2012 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()
: ZwSetIntervalProfile(NULL),
ZwQueryIntervalProfile(NULL),
ZwCreateProfile(NULL),
ZwStartProfile(NULL),
ZwStopProfile(NULL),
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>::Leaky 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
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