[Wayland-bugs] [Bug 106736] Weston almost halves *visible* frame update rate from what application actually produces

[bugzilla-daemon at freedesktop.org]

https://bugs.freedesktop.org/show_bug.cgi?id=106736

--- Comment #7 from Eero Tamminen <eero.t.tamminen at intel.com> ---
Unfortunately it seems that Mesa LIBGL_SHOW_FPS=1 doesn't work with Weston or
glmark2, so one needs to use some other means to measure FPS (like I do).


(In reply to Chris Wilson from comment #3)
> Would a test case that just calls *SwapBuffers() at a fixed frequency be
> good enough? And using glXGetSyncValuesOML or equiv to check the
> presentation jitter as exposed to the application. (E.g.
> piglit/tests/spec/glx_oml_sync_control/timing.c)

I wasn't able to reproduce the problem with simple-egl test, e.g. with:
  weston-simple-egl -b -o -u 15000

But that doesn't seem to use *SwapBuffers().

I'm not sure whether SwapBuffers() is the only reason why it doesn't trigger
the issue.  Maybe the test-case actually need to also fully use GPU, for this
issue to be visible.


These *do* reproduce the problem though:
  glmark2-wayland --annotate -b refract -s WxH
  glmark2-wayland --annotate -b terrain -s WxH

(--annotate option shows the FPS on screen. You can get it e.g. on Ubuntu just
with "sudo apt install glmark2-wayland".)

Just increase the window size W & H parameters until reported FPS is somewhere
between 70-100 FPS.

If you have even a slightly faster machine, even "refract" test is too fast. 
But if you can get it to suitable FPS range, it works exactly like the cases I
tested earlier (GpuTop v0.7 tests & internal Wayland benchmark).

However, the "terrain" test is worse than the other test-cases.  Increasing the
repaint-window value from default 7 to 15, will improve Weston FPS from initial
30 FPS to higher value, but it still doesn't get close to the expected 60 FPS.

-> I assume in that particular case, compositor would also require higher GPU
priority than the test.  Setting priorities is fairly new Mesa (and i915 kernel
module) feature.

-- 
You are receiving this mail because:
You are the assignee for the bug.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.freedesktop.org/archives/wayland-bugs/attachments/20180601/eb3e9e8d/attachment.html>