If we unwind the active requests, and on resubmission discover that we intend to preempt the active context with itself, simply skip the ELSP submission.
Signed-off-by: Chris Wilson chris@chris-wilson.co.uk --- drivers/gpu/drm/i915/gt/intel_lrc.c | 17 ++++++++++++++++- 1 file changed, 16 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/i915/gt/intel_lrc.c b/drivers/gpu/drm/i915/gt/intel_lrc.c index 431d3b8c3371..3cfea1758fd2 100644 --- a/drivers/gpu/drm/i915/gt/intel_lrc.c +++ b/drivers/gpu/drm/i915/gt/intel_lrc.c @@ -1739,11 +1739,26 @@ static void execlists_dequeue(struct intel_engine_cs *engine)
if (submit) { *port = execlists_schedule_in(last, port - execlists->pending); - memset(port + 1, 0, (last_port - port) * sizeof(*port)); execlists->switch_priority_hint = switch_prio(engine, *execlists->pending); + + /* + * Skip if we ended up with exactly the same set of requests, + * e.g. trying to timeslice a pair of ordered contexts + */ + if (!memcmp(execlists->active, execlists->pending, + (port - execlists->pending + 1) * sizeof(*port))) { + do + execlists_schedule_out(fetch_and_zero(port)); + while (port-- != execlists->pending); + + goto skip_submit; + } + + memset(port + 1, 0, (last_port - port) * sizeof(*port)); execlists_submit_ports(engine); } else { +skip_submit: ring_set_paused(engine, 0); } }