Disable flushers on CrOS to improve GPU process saturation during bulk texture uploads

We might want to have a flame war about this. But my intuition is that this is
a net-win, and that in the long run, this behavior should be up in WebGL
somewhere and that the compositor and ganesh should flush manually.

BUG=120548
R=jbates@chromium.org,jamesr@chromium.org,marcheu@chromium.org,piman@chromium.org

Review URL: https://chromiumcodereview.appspot.com/9809013

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@129313 0039d316-1c4b-4281-b951-d872f2087c98

2 files changed, 8 insertions, 1 deletions

diff --git a/gpu/command_buffer/client/cmd_buffer_helper.cc b/gpu/command_buffer/client/cmd_buffer_helper.cc
index 29770b8..f78bc34 100644
--- a/gpu/command_buffer/client/cmd_buffer_helper.cc
+++ b/gpu/command_buffer/client/cmd_buffer_helper.cc
@@ -229,7 +229,7 @@ void CommandBufferHelper::WaitForAvailableEntries(int32 count) {
   if (pending > limit) {
     Flush();
   } else if (commands_issued_ % kCommandsPerFlushCheck == 0) {
-#if !defined(OS_ANDROID)
+#if !defined(OS_ANDROID) && !defined(OS_CHROMEOS)
     // Allow this command buffer to be pre-empted by another if a "reasonable"
     // amount of work has been done. On highend machines, this reduces the
     // latency of GPU commands. However, on Android, this can cause the
diff --git a/gpu/command_buffer/client/gles2_implementation.cc b/gpu/command_buffer/client/gles2_implementation.cc
index 504eca1..cf55bb1 100644
--- a/gpu/command_buffer/client/gles2_implementation.cc
+++ b/gpu/command_buffer/client/gles2_implementation.cc
@@ -2694,7 +2694,12 @@ void GLES2Implementation::UnmapBufferSubDataCHROMIUM(const void* mem) {
   helper_->BufferSubData(
       mb.target, mb.offset, mb.size, mb.shm_id, mb.shm_offset);
   mapped_memory_->FreePendingToken(mb.shm_memory, helper_->InsertToken());
+  // Flushing after unmap lets the service side start processing commands
+  // sooner. However, on lowend devices, the thread thrashing causes is
+  // worse than the latency hit.
+#if !defined(OS_ANDROID) && !defined(OS_CHROMEOS)
   helper_->CommandBufferHelper::Flush();
+#endif
   mapped_buffers_.erase(it);
 }
 
@@ -2767,7 +2772,9 @@ void GLES2Implementation::UnmapTexSubImage2DCHROMIUM(const void* mem) {
       mt.target, mt.level, mt.xoffset, mt.yoffset, mt.width, mt.height,
       mt.format, mt.type, mt.shm_id, mt.shm_offset, GL_FALSE);
   mapped_memory_->FreePendingToken(mt.shm_memory, helper_->InsertToken());
+#if !defined(OS_ANDROID) && !defined(OS_CHROMEOS)
   helper_->CommandBufferHelper::Flush();
+#endif
   mapped_textures_.erase(it);
 }