> I have been working on adding vblank synchronization to the i915 driver and > I'm running into a performance problem. I was hoping someone that has done > this type of thing before might have run into this problem with another > driver.
How have you added it? by changing the page flip path?? (adding wait for vsync to the pageflip command?) I've got about 80% of it implemented here, along the lines of the other DRI drivers (radeon etc..) where we wait for the frame to finish and then wait for vblank, but it isn't suitable for code drop (i.e. it doesn't actually work yet)... > couple of OpenGL demo programs to test. One of the demo programs only gets > 16 to 18 FPS. This program gets up to 100 FPS when vblank sync is disabled. > I have done some profiling and have discovered a few things. The problem does > not seem to be with waiting for a vblank. intelPageFlip always completes > within 16ms which makes sense because my refresh is set to 60 Hz. What I am > seeing is that intelWaitIrq often takes up to 100ms when it should normally > take around 8ms with this test program. my guess is if you are using the page flip sync the ring buffer is waiting for the next vsync... granted 100ms just seems all wrong.. Dave. -- David Airlie, Software Engineer http://www.skynet.ie/~airlied / airlied at skynet.ie Linux kernel - DRI, VAX / pam_smb / ILUG ------------------------------------------------------- This SF.net email is sponsored by: Splunk Inc. Do you grep through log files for problems? Stop! Download the new AJAX search engine that makes searching your log files as easy as surfing the web. DOWNLOAD SPLUNK! http://ads.osdn.com/?ad_id=7637&alloc_id=16865&op=click -- _______________________________________________ Dri-devel mailing list Dri-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/dri-devel
