gpu/command_buffer/service/gpu_tracer.cc

// 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 "gpu/command_buffer/service/gpu_tracer.h"

#include <deque>

#include "base/bind.h"
#include "base/debug/trace_event.h"
#include "base/strings/string_util.h"
#include "base/time/time.h"
#include "gpu/command_buffer/common/gles2_cmd_utils.h"

namespace gpu {
namespace gles2 {

static const unsigned int kProcessInterval = 16;
static TraceOutputter* g_outputter_thread = NULL;

TraceMarker::TraceMarker(const std::string& name)
    : name_(name),
      trace_(NULL) {
}

TraceMarker::~TraceMarker() {
}

scoped_refptr<TraceOutputter> TraceOutputter::Create(const std::string& name) {
  if (!g_outputter_thread) {
    g_outputter_thread = new TraceOutputter(name);
  }
  return g_outputter_thread;
}

TraceOutputter::TraceOutputter(const std::string& name)
    : named_thread_(name.c_str()), local_trace_id_(0) {
  named_thread_.Start();
  named_thread_.Stop();
}

TraceOutputter::~TraceOutputter() { g_outputter_thread = NULL; }

void TraceOutputter::Trace(const std::string& name,
                           int64 start_time,
                           int64 end_time) {
  TRACE_EVENT_COPY_BEGIN_WITH_ID_TID_AND_TIMESTAMP0(
      TRACE_DISABLED_BY_DEFAULT("gpu.device"),
      name.c_str(),
      local_trace_id_,
      named_thread_.thread_id(),
      start_time);
  TRACE_EVENT_COPY_END_WITH_ID_TID_AND_TIMESTAMP0(
      TRACE_DISABLED_BY_DEFAULT("gpu.device"),
      name.c_str(),
      local_trace_id_,
      named_thread_.thread_id(),
      end_time);
  ++local_trace_id_;
}

GPUTrace::GPUTrace(const std::string& name)
    : name_(name),
      outputter_(NULL),
      offset_(0),
      end_time_(0),
      end_requested_(false),
      enabled_(false) {
}

GPUTrace::GPUTrace(scoped_refptr<Outputter> outputter,
                   const std::string& name,
                   int64 offset)
    : name_(name),
      outputter_(outputter),
      offset_(offset),
      start_time_(0),
      end_time_(0),
      end_requested_(false),
      enabled_(true) {
  glGenQueries(2, queries_);
}

GPUTrace::~GPUTrace() {
  if (enabled_)
    glDeleteQueries(2, queries_);
}

void GPUTrace::Start() {
  TRACE_EVENT_COPY_ASYNC_BEGIN0(
      TRACE_DISABLED_BY_DEFAULT("gpu.service"), name().c_str(), this);
  if (enabled_) {
    glQueryCounter(queries_[0], GL_TIMESTAMP);
  }
}

void GPUTrace::End() {
  if (enabled_) {
    glQueryCounter(queries_[1], GL_TIMESTAMP);
    end_requested_ = true;
  }

  TRACE_EVENT_COPY_ASYNC_END0(
      TRACE_DISABLED_BY_DEFAULT("gpu.service"), name().c_str(), this);
}

bool GPUTrace::IsAvailable() {
  if (!enabled_)
    return true;
  else if (!end_requested_)
    return false;

  GLint done = 0;
  glGetQueryObjectiv(queries_[1], GL_QUERY_RESULT_AVAILABLE, &done);
  return !!done;
}

void GPUTrace::Process() {
  if (!enabled_)
    return;

  DCHECK(IsAvailable());

  GLuint64 timestamp;

  // TODO(dsinclair): It's possible for the timer to wrap during the start/end.
  // We need to detect if the end is less then the start and correct for the
  // wrapping.
  glGetQueryObjectui64v(queries_[0], GL_QUERY_RESULT, &timestamp);
  start_time_ = (timestamp / base::Time::kNanosecondsPerMicrosecond) + offset_;

  glGetQueryObjectui64v(queries_[1], GL_QUERY_RESULT, &timestamp);
  end_time_ = (timestamp / base::Time::kNanosecondsPerMicrosecond) + offset_;

  glDeleteQueries(2, queries_);
  outputter_->Trace(name(), start_time_, end_time_);
}

GPUTracer::GPUTracer(gles2::GLES2Decoder* decoder)
    : gpu_trace_srv_category(TRACE_EVENT_API_GET_CATEGORY_GROUP_ENABLED(
          TRACE_DISABLED_BY_DEFAULT("gpu.service"))),
      gpu_trace_dev_category(TRACE_EVENT_API_GET_CATEGORY_GROUP_ENABLED(
          TRACE_DISABLED_BY_DEFAULT("gpu.device"))),
      decoder_(decoder),
      timer_offset_(0),
      last_tracer_source_(kTraceGroupInvalid),
      enabled_(false),
      gpu_timing_synced_(false),
      gpu_executing_(false),
      process_posted_(false) {
  if (gfx::g_driver_gl.ext.b_GL_ARB_timer_query) {
    outputter_ = TraceOutputter::Create("GL_ARB_timer_query");
    enabled_ = true;
  }
}

GPUTracer::~GPUTracer() {
}

bool GPUTracer::BeginDecoding() {
  if (enabled_) {
    if (*gpu_trace_dev_category) {
      // Make sure timing is synced before tracing
      if (!gpu_timing_synced_) {
        CalculateTimerOffset();
        gpu_timing_synced_ = true;
      }
    } else {
      // If GPU device category is off, invalidate timing sync
      gpu_timing_synced_ = false;
    }
  }

  if (gpu_executing_)
    return false;

  gpu_executing_ = true;

  if (IsTracing()) {
    // Begin a Trace for all active markers
    for (int n = 0; n < NUM_TRACER_SOURCES; n++) {
      for (size_t i = 0; i < markers_[n].size(); i++) {
        markers_[n][i].trace_ = CreateTrace(markers_[n][i].name_);
        markers_[n][i].trace_->Start();
      }
    }
  }
  return true;
}

bool GPUTracer::EndDecoding() {
  if (!gpu_executing_)
    return false;

  // End Trace for all active markers
  if (IsTracing()) {
    for (int n = 0; n < NUM_TRACER_SOURCES; n++) {
      for (size_t i = 0; i < markers_[n].size(); i++) {
        if (markers_[n][i].trace_.get()) {
          markers_[n][i].trace_->End();
          if (markers_[n][i].trace_->IsEnabled())
            traces_.push_back(markers_[n][i].trace_);
          markers_[n][i].trace_ = 0;
        }
      }
    }
    IssueProcessTask();
  }

  gpu_executing_ = false;

  // NOTE(vmiura): glFlush() here can help give better trace results,
  // but it distorts the normal device behavior.
  return true;
}

bool GPUTracer::Begin(const std::string& name, GpuTracerSource source) {
  if (!gpu_executing_)
    return false;

  DCHECK(source >= 0 && source < NUM_TRACER_SOURCES);

  // Push new marker from given 'source'
  last_tracer_source_ = source;
  markers_[source].push_back(TraceMarker(name));

  // Create trace
  if (IsTracing()) {
    scoped_refptr<GPUTrace> trace = CreateTrace(name);
    trace->Start();
    markers_[source].back().trace_ = trace;
  }

  return true;
}

bool GPUTracer::End(GpuTracerSource source) {
  if (!gpu_executing_)
    return false;

  DCHECK(source >= 0 && source < NUM_TRACER_SOURCES);

  // Pop last marker with matching 'source'
  if (!markers_[source].empty()) {
    if (IsTracing()) {
      scoped_refptr<GPUTrace> trace = markers_[source].back().trace_;
      if (trace.get()) {
        trace->End();
        if (trace->IsEnabled())
          traces_.push_back(trace);
        IssueProcessTask();
      }
    }

    markers_[source].pop_back();
    return true;
  }
  return false;
}

bool GPUTracer::IsTracing() {
  return (*gpu_trace_srv_category != 0) || (*gpu_trace_dev_category != 0);
}

const std::string& GPUTracer::CurrentName() const {
  if (last_tracer_source_ >= 0 &&
      last_tracer_source_ < NUM_TRACER_SOURCES &&
      !markers_[last_tracer_source_].empty()) {
    return markers_[last_tracer_source_].back().name_;
  }
  return base::EmptyString();
}

scoped_refptr<GPUTrace> GPUTracer::CreateTrace(const std::string& name) {
  if (enabled_ && *gpu_trace_dev_category)
    return new GPUTrace(outputter_, name, timer_offset_);
  else
    return new GPUTrace(name);
}

void GPUTracer::Process() {
  process_posted_ = false;
  ProcessTraces();
  IssueProcessTask();
}

void GPUTracer::ProcessTraces() {
  if (!enabled_) {
    while (!traces_.empty() && traces_.front()->IsAvailable()) {
      traces_.front()->Process();
      traces_.pop_front();
    }
    return;
  }

  TRACE_EVENT0("gpu", "GPUTracer::ProcessTraces");

  // Make owning decoder's GL context current
  if (!decoder_->MakeCurrent()) {
    // Skip subsequent GL calls if MakeCurrent fails
    traces_.clear();
    return;
  }

  while (!traces_.empty() && traces_.front()->IsAvailable()) {
    traces_.front()->Process();
    traces_.pop_front();
  }

  // Clear pending traces if there were are any errors
  GLenum err = glGetError();
  if (err != GL_NO_ERROR)
    traces_.clear();
}

void GPUTracer::CalculateTimerOffset() {
  if (enabled_) {
    TRACE_EVENT0("gpu", "GPUTracer::CalculateTimerOffset");

    // NOTE(vmiura): It would be better to use glGetInteger64v, however
    // it's not available everywhere.
    GLuint64 gl_now = 0;
    GLuint query;
    glFinish();
    glGenQueries(1, &query);
    glQueryCounter(query, GL_TIMESTAMP);
    glFinish();
    glGetQueryObjectui64v(query, GL_QUERY_RESULT, &gl_now);
    base::TimeTicks system_now = base::TimeTicks::NowFromSystemTraceTime();

    gl_now /= base::Time::kNanosecondsPerMicrosecond;
    timer_offset_ = system_now.ToInternalValue() - gl_now;
    glDeleteQueries(1, &query);
  }
}

void GPUTracer::IssueProcessTask() {
  if (traces_.empty() || process_posted_)
    return;

  process_posted_ = true;
  base::MessageLoop::current()->PostDelayedTask(
      FROM_HERE,
      base::Bind(&GPUTracer::Process, base::AsWeakPtr(this)),
      base::TimeDelta::FromMilliseconds(kProcessInterval));
}

}  // namespace gles2
}  // namespace gpu