| commit | b11fa8eac21ce758d71825666a36cb8b534b6d85 | [log] [tgz] |
|---|---|---|
| author | Lingfeng Yang <lfy@google.com> | Fri Jul 22 15:21:58 2016 -0700 |
| committer | Lingfeng Yang <lfy@google.com> | Thu Jul 28 10:05:28 2016 -0700 |
| tree | aff173b21e63625901cdaaf3ac0efd6b131ea982 | |
| parent | 7f5385ad2ac0f1870a5e71ed5f5b606d829d4c2c [diff] |
More efficient swapBuffers Previously, we were using glFinish() in the host to make sure that a buffer that we are presenting has been completely written to. That is bad for performance, because it usually means to block the CPU until the GPU's command queue is completely empty and all operations have completed. This CL uses eglCreateSyncKHR with a native fence FD to guarantee the draw buffer is finished before presenting. The idea is that after rcFlushWindowColorBufferAsync has queued up GPU commands to finish up the draw buffer, eglCreateSyncKHR follows that up with a fence command. The fence command in turn is represented by a FD (by providing EGL_SYNC_NATIVE_FENCE_ANDROID as the sync object type). Giving that FD to queueBuffer tells SurfaceFlinger/BufferQueue not to do anything that depends on the contents of that buffer until the fence command has completed. Theoretically, we are supposed to wait on the FD coming from dequeueBuffer as well, to make sure no one else is using it, but in practice, it matters much less; we will just overwrite the contents anyway, and it has not proved to be any problem in terms of visual artifacts. This is part of a sequential, multi-CL change. There is also a corresponding multi-CL change on the host side: https://android-review.googlesource.com/#/q/topic:emu-glsync-host The changes in the system image are as follows: platform/build: https://googleplex-android-review.git.corp.google.com/1024926 device/generic/goldfish: https://googleplex-android-review.git.corp.google.com/1230942 device/generic/goldfish-opengl: https://googleplex-android-review.git.corp.google.com/1219535 https://googleplex-android-review.git.corp.google.com/1219536 https://googleplex-android-review.git.corp.google.com/1219537 https://googleplex-android-review.git.corp.google.com/1219538 https://googleplex-android-review.git.corp.google.com/1219539 https://googleplex-android-review.git.corp.google.com/1219570 <- needed https://googleplex-android-review.git.corp.google.com/1219571 <- this CL Change-Id: I3dd1b69c77665ac0143bd5a302e6a5a04736c9ea