Re: [Intel-gfx] [PATCH v3] drm/i915: Queue page flip work via a low latency, unbound workqueue
Op 20-09-16 om 14:51 schreef Chris Wilson: > On Tue, Sep 20, 2016 at 02:58:19PM +0300, Imre Deak wrote: >> While user space has control over the scheduling priority of its page >> flipping thread, the corresponding work the driver schedules for MMIO >> flips always runs from the generic system workqueue which has some >> scheduling overhead due it being CPU bound. This would hinder an >> application that wants more stringent guarantees over flip timing (to >> avoid missing a flip at the next frame count). >> >> Fix this by scheduling the work from the unbound system workqueue >> which provides for minimal scheduling latency. >> >> v2: >> - Use an unbound workqueue instead of a high-prio one. (Tvrtko, Chris) >> v3: >> - Use the system unbound wq instead of a dedicated one. (Maarten) >> >> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=97775 >> Testcase: igt/kms_cursor_legacy >> CC: Chris Wilson >> CC: Maarten Lankhorst >> CC: Tvrtko Ursulin >> Signed-off-by: Imre Deak >> Reviewed-by: Tvrtko Ursulin (v1) > We violate the unbound_wq rules no worse than the ordinary system_wq, > and this brings mmioflip on a par with nonblocking atomic modesets, so > Reviewed-by: Chris Wilson > -Chris > Reviewed-by: Maarten Lankhorst ___ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/intel-gfx
Re: [Intel-gfx] [PATCH v3] drm/i915: Queue page flip work via a low latency, unbound workqueue
On Tue, Sep 20, 2016 at 02:58:19PM +0300, Imre Deak wrote: > While user space has control over the scheduling priority of its page > flipping thread, the corresponding work the driver schedules for MMIO > flips always runs from the generic system workqueue which has some > scheduling overhead due it being CPU bound. This would hinder an > application that wants more stringent guarantees over flip timing (to > avoid missing a flip at the next frame count). > > Fix this by scheduling the work from the unbound system workqueue > which provides for minimal scheduling latency. > > v2: > - Use an unbound workqueue instead of a high-prio one. (Tvrtko, Chris) > v3: > - Use the system unbound wq instead of a dedicated one. (Maarten) > > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=97775 > Testcase: igt/kms_cursor_legacy > CC: Chris Wilson > CC: Maarten Lankhorst > CC: Tvrtko Ursulin > Signed-off-by: Imre Deak > Reviewed-by: Tvrtko Ursulin (v1) We violate the unbound_wq rules no worse than the ordinary system_wq, and this brings mmioflip on a par with nonblocking atomic modesets, so Reviewed-by: Chris Wilson -Chris -- Chris Wilson, Intel Open Source Technology Centre ___ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/intel-gfx
