tree 4d590ff1f9a65223a85ef5ed8666020c4c2a317f
parent 6e57cc39420c1d13d92c46ea662a7f9f5368f2ee
author Chris Wilson <chris@chris-wilson.co.uk> 1582895832 +0000
committer Chris Wilson <chris@chris-wilson.co.uk> 1582927419 +0000

drm/i915/gt: Expose timeslice duration to sysfs

Execlists uses a scheduling quantum (a timeslice) to alternate execution
between ready-to-run contexts of equal priority. This ensures that all
users (though only if they of equal importance) have the opportunity to
run and prevents livelocks where contexts may have implicit ordering due
to userspace semaphores.

The timeslicing mechanism can be compiled out with

	./scripts/config --set-val DRM_I915_TIMESLICE_DURATION 0

The timeslice duration can be adjusted per-engine using,

	/sys/class/drm/card?/engine/*/timeslice_duration_ms

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Reviewed-by: Steve Carbonari <steven.carbonari@intel.com>
Tested-by: Steve Carbonari <steven.carbonari@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200228131716.3243616-3-chris@chris-wilson.co.uk