Add back in code to flush command buffer every 3 ms

Not having this code causes WebGL and NaCl apps to not flush as often as they should, and build up huge command buffers.

BUG=152393


Review URL: https://chromiumcodereview.appspot.com/11031032

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@160070 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 15 insertions, 0 deletions

diff --git a/gpu/command_buffer/client/cmd_buffer_helper.cc b/gpu/command_buffer/client/cmd_buffer_helper.cc
index 3dcc318..d556b5e 100644
--- a/gpu/command_buffer/client/cmd_buffer_helper.cc
+++ b/gpu/command_buffer/client/cmd_buffer_helper.cc
@@ -10,6 +10,11 @@
 
 namespace gpu {
 
+namespace {
+const int kCommandsPerFlushCheck = 100;
+const double kFlushDelay = 1.0 / (5.0 * 60.0);
+}
+
 CommandBufferHelper::CommandBufferHelper(CommandBuffer* command_buffer)
     : command_buffer_(command_buffer),
       ring_buffer_id_(-1),
@@ -236,6 +241,16 @@ void CommandBufferHelper::WaitForAvailableEntries(int32 count) {
       ((get_offset() == last_put_sent_) ? 16 : 2);
   if (pending > limit) {
     Flush();
+  } else if (commands_issued_ % kCommandsPerFlushCheck == 0) {
+#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
+    // kernel to thrash between generating GPU commands and executing them.
+    clock_t current_time = clock();
+    if (current_time - last_flush_time_ > kFlushDelay * CLOCKS_PER_SEC)
+      Flush();
+#endif
   }
 }