About fastpath mode in screen latency test

[buddhist182]

There is fastpath mode in screen latency test, In the code it invoke "setSharedBufferMode" method which means use single Buffer to render and display. But from the systrace of fastpath test, the graphicBuffer was dequeued and queued normally, and there is 2 graphicBuffer:SurfaceView - org.chromium.latency.walt/org.chromium.latency.walt.MainActivity#0:0 and SurfaceView - org.chromium.latency.walt/org.chromium.latency.walt.MainActivity#0: 1。

So the queston is:

1. Does fastpath mode use the single Buffer mode?
2. If so, why the fastpath mode use 2 graphic Buffer, does it need hardware support?
   Thanks!

[kamrik]

I don't know much about the fast path mode. As far as I remember, the code for fast path mode was taken from some example I got from another team. My guess would also be that this behaviour heavily depends on hardware or drivers.

[buddhist182]

Thanks for your reply!
The fastpath related code is too old such as method "setSharedBufferMode", which has been changed to "setSharedBufferModeEnabled", I have changed this method and add method "setAutoRefreshEnabled' to enable the single Buffer, but it also need the GPU EGL_SINGLE_BUFFER mode support, and I do not know hoow to enable it.
can you help to complete the fastpath test mode code, Thanks!

[buddhist182]

Thanks for your reply!
The fastpath related code is too old such as method "setSharedBufferMode", which has been changed to "setSharedBufferModeEnabled", I have changed this method and add method "setAutoRefreshEnabled' to enable the single Buffer, but it also need the GPU EGL_SINGLE_BUFFER mode support, and I do not know hoow to enable it.
can you help to complete the fastpath test mode code, Thanks!

[kamrik]

I don't think I will be able to help you, I don't know much about low level graphics code on Android & Linux. Sorry.