From: John Harrison John.C.Harrison@Intel.com
Compute workloads are inherently not pre-emptible for long periods on current hardware. As a workaround for this, the pre-emption timeout for compute capable engines was disabled. This is undesirable with GuC submission as it prevents per engine reset of hung contexts. Hence the next patch will re-enable the timeout but bumped up by an order of magnitude.
However, the heartbeat might not respect that. Depending upon current activity, a pre-emption to the heartbeat pulse might not even be attempted until the last heartbeat period. Which means that only one period is granted for the pre-emption to occur. With the aforesaid bump, the pre-emption timeout could be significantly larger than this heartbeat period.
So adjust the heartbeat code to take the pre-emption timeout into account. When it reaches the final (high priority) period, it now ensures the delay before hitting reset is bigger than the pre-emption timeout.
v2: Fix for selftests which adjust the heartbeat period manually.
Signed-off-by: John Harrison John.C.Harrison@Intel.com --- .../gpu/drm/i915/gt/intel_engine_heartbeat.c | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+)
diff --git a/drivers/gpu/drm/i915/gt/intel_engine_heartbeat.c b/drivers/gpu/drm/i915/gt/intel_engine_heartbeat.c index a3698f611f45..0dc53def8e42 100644 --- a/drivers/gpu/drm/i915/gt/intel_engine_heartbeat.c +++ b/drivers/gpu/drm/i915/gt/intel_engine_heartbeat.c @@ -22,9 +22,27 @@
static bool next_heartbeat(struct intel_engine_cs *engine) { + struct i915_request *rq; long delay;
delay = READ_ONCE(engine->props.heartbeat_interval_ms); + + rq = engine->heartbeat.systole; + + if (rq && rq->sched.attr.priority >= I915_PRIORITY_BARRIER && + delay == engine->defaults.heartbeat_interval_ms) { + long longer; + + /* + * The final try is at the highest priority possible. Up until now + * a pre-emption might not even have been attempted. So make sure + * this last attempt allows enough time for a pre-emption to occur. + */ + longer = READ_ONCE(engine->props.preempt_timeout_ms) * 2; + if (longer > delay) + delay = longer; + } + if (!delay) return false;