GpuVSyncProvider with unit test

gpu/ipc/service/gpu_vsync_provider_win.cc

+// Copyright (c) 2016 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/ipc/service/gpu_vsync_provider.h"
+
+#include "base/bind.h"
+#include "base/strings/stringprintf.h"
+#include "base/trace_event/trace_event.h"
+
+#include <windows.h>
+
+namespace gpu {
+
+namespace {
+// from <D3dkmthk.h>
+typedef LONG NTSTATUS;
+typedef UINT D3DKMT_HANDLE;
+typedef UINT D3DDDI_VIDEO_PRESENT_SOURCE_ID;
+
+#define STATUS_SUCCESS ((NTSTATUS)0x00000000L)
+
+typedef struct _D3DKMT_OPENADAPTERFROMHDC {
+  HDC hDc;
+  D3DKMT_HANDLE hAdapter;
+  LUID AdapterLuid;
+  D3DDDI_VIDEO_PRESENT_SOURCE_ID VidPnSourceId;
+} D3DKMT_OPENADAPTERFROMHDC;
+
+typedef struct _D3DKMT_CLOSEADAPTER {
+  D3DKMT_HANDLE hAdapter;
+} D3DKMT_CLOSEADAPTER;
+
+typedef struct _D3DKMT_WAITFORVERTICALBLANKEVENT {
+  D3DKMT_HANDLE hAdapter;
+  D3DKMT_HANDLE hDevice;
+  D3DDDI_VIDEO_PRESENT_SOURCE_ID VidPnSourceId;
+} D3DKMT_WAITFORVERTICALBLANKEVENT;
+
+typedef NTSTATUS(APIENTRY* PFND3DKMTOPENADAPTERFROMHDC)(
+    D3DKMT_OPENADAPTERFROMHDC*);
+typedef NTSTATUS(APIENTRY* PFND3DKMTCLOSEADAPTER)(D3DKMT_CLOSEADAPTER*);
+typedef NTSTATUS(APIENTRY* PFND3DKMTWAITFORVERTICALBLANKEVENT)(
+    D3DKMT_WAITFORVERTICALBLANKEVENT*);
+}  // namespace
+
+/* static */
+std::unique_ptr<GpuVSyncProvider> GpuVSyncProvider::Create(
+    const VSyncCallback& callback,
+    SurfaceHandle surface_handle) {
+  std::unique_ptr<GpuVSyncProvider> provider(
+      new GpuVSyncProvider(callback, surface_handle));
+  // Start the thread.
+  base::Thread::Options options;
+  // TODO(stanisc): might consider even higher priority - REALTIME_AUDIO.
+  options.priority = base::ThreadPriority::DISPLAY;
+  provider->StartWithOptions(options);
+  return provider;
+}
+
+GpuVSyncProvider::GpuVSyncProvider(const VSyncCallback& callback,
+                                   SurfaceHandle surface_handle)
+    : base::Thread(base::StringPrintf("VSync-%d", surface_handle)),
+      callback_(callback),
+      surface_handle_(surface_handle) {}
+
+GpuVSyncProvider::~GpuVSyncProvider() {
+  Stop();
+}
+
+void GpuVSyncProvider::EnableVSync(bool enabled) {
+  if (enabled_ == enabled)
+    return;
+
+  enabled_ = enabled;
+
+  if (enabled_)
+    task_runner()->PostTask(
+        FROM_HERE, base::Bind(&GpuVSyncProvider::StartRunningVSyncOnThread,
+                              base::Unretained(this)));
+}
+
+void GpuVSyncProvider::StartRunningVSyncOnThread() {
+  DCHECK(base::PlatformThread::CurrentId() == GetThreadId());
+
+  if (!running_) {
+    running_ = true;
+    WaitForVSyncOnThread();
+  }
+}
+
+void GpuVSyncProvider::WaitForVSyncOnThread() {

[brucedawson, 2016/12/22 21:49:16]

Do we really want this to do the whole init/de-init dance for every vblank?

I would expect that we would set up all of the state and then reuse it. Is there
a need (monitor changes perhaps) for redoing all of the work?

Should at least be able to cache the function pointers.

[stanisc, 2016/12/22 22:59:31]

One reason I've done it this way is because I wanted to avoid leaking these
implementation details into the header file. This function pointers are windows
specific and the header file is supported on all platforms.

It seems that getting this function pointers every time isn't a big deal - I
profiled this code and the CPU cost of this code was fairly negligible. I agree
that I could reuse at least the function pointers.

What I could do is to move the background worker implementation into a separate
class defined locally in this file. I think that is a good idea.

[stanisc, 2017/01/04 22:33:04]

OK. Cached function pointers, but keep opening/closing adapter every time. I
think it not worth the extra complexity considering this is called only 60 times
per second. It doesn't look like this open/close calls are expensive.

+  DCHECK(base::PlatformThread::CurrentId() == GetThreadId());
+
+  TRACE_EVENT0("gpu", "GpuVSyncProvider::WaitForVSyncOnThread");
+
+  // TODO: implement this

[brucedawson, 2016/12/22 21:49:16]

I don't understand this comment.

[stanisc, 2016/12/22 22:59:31]

Forgot to remove this one. Will remove it in the next change.

[stanisc, 2017/01/04 22:33:04]

Done.

+  HMODULE gdi32 = GetModuleHandle(L"gdi32");
+  if (!gdi32) {
+    NOTREACHED() << "Can't open gdi32.dll";
+    return;
+  }
+
+  auto open_adapter_from_hdc_ptr =
+      reinterpret_cast<PFND3DKMTOPENADAPTERFROMHDC>(
+          ::GetProcAddress(gdi32, "D3DKMTOpenAdapterFromHdc"));
+  if (!open_adapter_from_hdc_ptr) {
+    NOTREACHED() << "Can't find D3DKMTOpenAdapterFromHdc in gdi32.dll";
+    return;
+  }
+
+  auto close_adapter_ptr = reinterpret_cast<PFND3DKMTCLOSEADAPTER>(
+      ::GetProcAddress(gdi32, "D3DKMTCloseAdapter"));
+  if (!close_adapter_ptr) {
+    NOTREACHED() << "Can't find D3DKMTCloseAdapter in gdi32.dll";
+    return;
+  }
+
+  auto wait_for_vertical_blank_event_ptr =
+      reinterpret_cast<PFND3DKMTWAITFORVERTICALBLANKEVENT>(
+          ::GetProcAddress(gdi32, "D3DKMTWaitForVerticalBlankEvent"));
+  if (!wait_for_vertical_blank_event_ptr) {
+    NOTREACHED() << "Can't find D3DKMTWaitForVerticalBlankEvent in gdi32.dll";
+    return;
+  }
+
+  HMONITOR monitor =
+      MonitorFromWindow(surface_handle_, MONITOR_DEFAULTTONEAREST);
+  MONITORINFOEX monitor_info;
+  monitor_info.cbSize = sizeof(MONITORINFOEX);
+  BOOL success = GetMonitorInfo(monitor, &monitor_info);
+  CHECK(success);
+
+  HDC hdc = CreateDC(NULL, monitor_info.szDevice, NULL, NULL);
+
+  D3DKMT_OPENADAPTERFROMHDC open_adapter_data;
+  open_adapter_data.hDc = hdc;
+
+  NTSTATUS result = open_adapter_from_hdc_ptr(&open_adapter_data);
+  DeleteDC(hdc);
+
+  CHECK(result == STATUS_SUCCESS);
+
+  D3DKMT_WAITFORVERTICALBLANKEVENT wait_for_vertical_blank_event_data;
+  wait_for_vertical_blank_event_data.hAdapter = open_adapter_data.hAdapter;
+  wait_for_vertical_blank_event_data.hDevice = 0;
+  wait_for_vertical_blank_event_data.VidPnSourceId =
+      open_adapter_data.VidPnSourceId;
+
+  result =
+      wait_for_vertical_blank_event_ptr(&wait_for_vertical_blank_event_data);
+  if (result == STATUS_SUCCESS) {
+    // Note: this sends update from the background thread.
+    SendVSyncUpdate(base::TimeTicks::Now());
+  }
+
+  D3DKMT_CLOSEADAPTER close_adapter_data;
+  close_adapter_data.hAdapter = open_adapter_data.hAdapter;
+
+  result = close_adapter_ptr(&close_adapter_data);
+  CHECK(result == STATUS_SUCCESS);
+
+  // Restart the task if still enabled.
+  if (enabled_) {
+    task_runner()->PostTask(FROM_HERE,
+                            base::Bind(&GpuVSyncProvider::WaitForVSyncOnThread,
+                                       base::Unretained(this)));
+  } else {
+    running_ = false;
+  }
+}
+
+void GpuVSyncProvider::SendVSyncUpdate(base::TimeTicks now) {
+  TRACE_EVENT0("gpu", "GpuVSyncProvider::SendVSync");

[stanisc, 2016/12/22 21:35:08]

Need to change this to SendVSyncUpdate

+  if (enabled_) {
+    callback_.Run(now);
+  }
+}
+
+}  // namespace gpu