Summary: "Video synchronization method"
Choose the method used to ensure video synchronization with the display.
Valid values are:
Value: auto (Auto)
Automaically choose sync method based on platform.
Value: swap (Swap)
Most basic method, but will probably not mantain emulation
perfectly in sync on many GPUs due to pipelining and the swap buffers
command returning before it is completed.
Value: swap-finish (Swap-Finish)
This method should force the emulation to be in sync with
the display, but glFinish may use a busy-loop and cause high CPU usage.
Value: finish-swap-finish (Finish-Swap-Finish)
Execute a glFinish also before swapping buffers.
May work better with some OpenGL drivers. Otherwise same as swap-finish
(High CPU usage with many drivers).
Value: finish-sleep-swap-finish (Finish-Sleep-Swap-Finish)
Same as above, but sleep before executing
the swap command. The sleep time is based on the (estimated) time left
to the next vblank. This should reduce the CPU usage a lot, but on some
systems/drivers, the display will not be synchronized properly.
Value: sleep-swap-finish (Sleep-Swap-Finish)
Same as above, but do not issue a glFinish before
starting the sleep. This should use less CPU than the above option, but
some drivers seem to need the finish before the sleep to achieve proper
Value: swap-fence (Swap-Fence)
Set a fence after swapping buffers and poll periodically
(with sleeps) for completion of swap. This seems to work very well on
Linux with recent nVIDIA drivers.
Value: swap-sleep-fence (Swap-Sleep-Fence)
Same as above, but sleep a while (based on estimated
time to next vblank) before starting to poll the fence, (in case the
test-fence method blocks with high CPU usage, problem seen on
The default value is:
* finish-sleep-swap-finish - for Windows and Mac OS X
* finish-swap-finish - for Linux.
See also [video_sync].