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<b><a class="bz_bug_link
bz_status_NEW "
title="NEW - With Vsync disabled, Weston almost halves *visible* frame update rate, compared to X desktop"
href="https://bugs.freedesktop.org/show_bug.cgi?id=106736#c12">Comment # 12</a>
on <a class="bz_bug_link
bz_status_NEW "
title="NEW - With Vsync disabled, Weston almost halves *visible* frame update rate, compared to X desktop"
href="https://bugs.freedesktop.org/show_bug.cgi?id=106736">bug 106736</a>
from <span class="vcard"><a class="email" href="mailto:eero.t.tamminen@intel.com" title="Eero Tamminen <eero.t.tamminen@intel.com>"> <span class="fn">Eero Tamminen</span></a>
</span></b>
<pre>(In reply to Daniel Stone from <a href="show_bug.cgi?id=106736#c8">comment #8</a>)
<span class="quote">> (In reply to Eero Tamminen from <a href="show_bug.cgi?id=106736#c7">comment #7</a>)
> > 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.
>
> It certainly does call eglSwapBuffers:
> <a href="https://gitlab.freedesktop.org/wayland/weston/blob/master/clients/simple-egl">https://gitlab.freedesktop.org/wayland/weston/blob/master/clients/simple-egl</a>.
> c#L568</span >
I see. I need to track eglSwapBuffersWithDamageEXT() instead. Thanks!
(eglSwapBuffers() is called exactly 3 times, and only on startup.)
<span class="quote">> > Just increase the window size W & H parameters until reported FPS is
> > somewhere between 70-100 FPS.
>
> So presumably it's running with eglSwapInterval(0) which doesn't block on
> frame callbacks at all?</span >
All gfx performance benchmarks run (by default) with Vsync disabled. They
cannot measure performance differences if they're limited by Vsync. :-)
<span class="quote">> > -> 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.
>
> We do use it:
> <a href="https://gitlab.freedesktop.org/wayland/weston/commit/">https://gitlab.freedesktop.org/wayland/weston/commit/</a>
> b678befb6ed055e6c66466505d9195a3cebf8073</span >
Weston logs:
Failed to obtain a high priority context.
I use latest git version of drm-tip kernel, Mesa, Weston, and weston-launch is
suid root. What else is needed for context priority setting to succeed?</pre>
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