Commit 4e5c8a99 authored by Chris Wilson's avatar Chris Wilson

drm/i915: Drop i915_request.lock requirement for intel_rps_boost()

Since we use a flag within i915_request.flags to indicate when we have
boosted the request (so that we only apply the boost) once, this can be
used as the serialisation with i915_request_retire() to avoid having to
explicitly take the i915_request.lock which is more heavily contended.
Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: default avatarMika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20201231093149.19086-1-chris@chris-wilson.co.uk
parent 9c080b0f
......@@ -578,7 +578,7 @@ static int rps_boost_show(struct seq_file *m, void *data)
intel_gpu_freq(rps, rps->efficient_freq),
intel_gpu_freq(rps, rps->boost_freq));
seq_printf(m, "Wait boosts: %d\n", atomic_read(&rps->boosts));
seq_printf(m, "Wait boosts: %d\n", READ_ONCE(rps->boosts));
if (INTEL_GEN(i915) >= 6 && intel_rps_is_active(rps)) {
struct intel_uncore *uncore = gt->uncore;
......
......@@ -862,6 +862,8 @@ void intel_rps_park(struct intel_rps *rps)
{
int adj;
GEM_BUG_ON(atomic_read(&rps->num_waiters));
if (!intel_rps_clear_active(rps))
return;
......@@ -917,28 +919,27 @@ void intel_rps_park(struct intel_rps *rps)
void intel_rps_boost(struct i915_request *rq)
{
if (i915_request_signaled(rq) || i915_request_has_waitboost(rq))
return;
/* Serializes with i915_request_retire() */
if (!test_and_set_bit(I915_FENCE_FLAG_BOOST, &rq->fence.flags)) {
struct intel_rps *rps = &READ_ONCE(rq->engine)->gt->rps;
unsigned long flags;
if (i915_request_signaled(rq) || !intel_rps_is_active(rps))
if (atomic_fetch_inc(&rps->num_waiters))
return;
/* Serializes with i915_request_retire() */
spin_lock_irqsave(&rq->lock, flags);
if (!i915_request_has_waitboost(rq) &&
!dma_fence_is_signaled_locked(&rq->fence)) {
set_bit(I915_FENCE_FLAG_BOOST, &rq->fence.flags);
if (!intel_rps_is_active(rps))
return;
GT_TRACE(rps_to_gt(rps), "boost fence:%llx:%llx\n",
rq->fence.context, rq->fence.seqno);
if (!atomic_fetch_inc(&rps->num_waiters) &&
READ_ONCE(rps->cur_freq) < rps->boost_freq)
if (READ_ONCE(rps->cur_freq) < rps->boost_freq)
schedule_work(&rps->work);
atomic_inc(&rps->boosts);
WRITE_ONCE(rps->boosts, rps->boosts + 1); /* debug only */
}
spin_unlock_irqrestore(&rq->lock, flags);
}
int intel_rps_set(struct intel_rps *rps, u8 val)
......
......@@ -93,7 +93,7 @@ struct intel_rps {
} power;
atomic_t num_waiters;
atomic_t boosts;
unsigned int boosts;
/* manual wa residency calculations */
struct intel_rps_ei ei;
......
......@@ -1232,7 +1232,7 @@ static int i915_rps_boost_info(struct seq_file *m, void *data)
intel_gpu_freq(rps, rps->efficient_freq),
intel_gpu_freq(rps, rps->boost_freq));
seq_printf(m, "Wait boosts: %d\n", atomic_read(&rps->boosts));
seq_printf(m, "Wait boosts: %d\n", READ_ONCE(rps->boosts));
if (INTEL_GEN(dev_priv) >= 6 && intel_rps_is_active(rps)) {
u32 rpup, rpupei;
......
......@@ -307,10 +307,8 @@ bool i915_request_retire(struct i915_request *rq)
spin_unlock_irq(&rq->lock);
}
if (i915_request_has_waitboost(rq)) {
GEM_BUG_ON(!atomic_read(&rq->engine->gt->rps.num_waiters));
if (test_and_set_bit(I915_FENCE_FLAG_BOOST, &rq->fence.flags))
atomic_dec(&rq->engine->gt->rps.num_waiters);
}
/*
* We only loosely track inflight requests across preemption,
......
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