Continuing the discussion with the latest refactorings, however I ran
some tests to measure the impact on system (!i915) latency,
using igt/benchmarks/gem_syslatency -t 120
drm-tip:
latency mean=1.211us max=10us (no load)
latency mean=2.611us max=83us (i915)
latency mean=1.720us max=833us (no load, bg writeout)
latency mean=3.294us max=607us (i915, bg writeout)
this series:
latency mean=1.280us max=15us (no load)
latency mean=9.688us max=1271us (i915)
latency mean=1.712us max=1026us (no load, bg writeout)
latency mean=14.347us max=489850us (i915, bg writeout)
That certainly takes the shine off directly using the tasklet for
submission from the irq handler. Being selfish, I still think we can't
allow the GPU to stall waiting for ksoftirqd, but at the same time we
need to solve the latency issues introduced elsewhere.
-Chris
_______________________________________________
Intel-gfx mailing list
Intel-gfx@xxxxxxxxxxxxxxxxxxxxx
https://lists.freedesktop.org/mailman/listinfo/intel-gfx
