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

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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: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20201231093149.19086-1-chris@chris-wilson.co.uk
This commit is contained in:
Chris Wilson 2020-12-31 09:31:49 +00:00
parent 9c080b0f96
commit 4e5c8a99e1
5 changed files with 17 additions and 18 deletions
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2
drivers/gpu/drm/i915/gt/debugfs_gt_pm.c
View file

@ -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->efficient_freq),
intel_gpu_freq(rps, rps->boost_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)) { if (INTEL_GEN(i915) >= 6 && intel_rps_is_active(rps)) {
struct intel_uncore *uncore = gt->uncore; struct intel_uncore *uncore = gt->uncore;

25
drivers/gpu/drm/i915/gt/intel_rps.c
View file

@ -862,6 +862,8 @@ void intel_rps_park(struct intel_rps *rps)
{ {
int adj; int adj;
GEM_BUG_ON(atomic_read(&rps->num_waiters));
if (!intel_rps_clear_active(rps)) if (!intel_rps_clear_active(rps))
return; return;
@ -917,28 +919,27 @@ void intel_rps_park(struct intel_rps *rps)
void intel_rps_boost(struct i915_request *rq) void intel_rps_boost(struct i915_request *rq)
{ {
struct intel_rps *rps = &READ_ONCE(rq->engine)->gt->rps; if (i915_request_signaled(rq) || i915_request_has_waitboost(rq))
unsigned long flags;
if (i915_request_signaled(rq) || !intel_rps_is_active(rps))
return; return;
/* Serializes with i915_request_retire() */ /* Serializes with i915_request_retire() */
spin_lock_irqsave(&rq->lock, flags); if (!test_and_set_bit(I915_FENCE_FLAG_BOOST, &rq->fence.flags)) {
if (!i915_request_has_waitboost(rq) && struct intel_rps *rps = &READ_ONCE(rq->engine)->gt->rps;
!dma_fence_is_signaled_locked(&rq->fence)) {
set_bit(I915_FENCE_FLAG_BOOST, &rq->fence.flags); if (atomic_fetch_inc(&rps->num_waiters))
return;
if (!intel_rps_is_active(rps))
return;
GT_TRACE(rps_to_gt(rps), "boost fence:%llx:%llx\n", GT_TRACE(rps_to_gt(rps), "boost fence:%llx:%llx\n",
rq->fence.context, rq->fence.seqno); rq->fence.context, rq->fence.seqno);
if (!atomic_fetch_inc(&rps->num_waiters) && if (READ_ONCE(rps->cur_freq) < rps->boost_freq)
READ_ONCE(rps->cur_freq) < rps->boost_freq)
schedule_work(&rps->work); 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) int intel_rps_set(struct intel_rps *rps, u8 val)

2
drivers/gpu/drm/i915/gt/intel_rps_types.h
View file

@ -93,7 +93,7 @@ struct intel_rps {
} power; } power;
atomic_t num_waiters; atomic_t num_waiters;
atomic_t boosts; unsigned int boosts;
/* manual wa residency calculations */ /* manual wa residency calculations */
struct intel_rps_ei ei; struct intel_rps_ei ei;

2
drivers/gpu/drm/i915/i915_debugfs.c
View file

@ -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->efficient_freq),
intel_gpu_freq(rps, rps->boost_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)) { if (INTEL_GEN(dev_priv) >= 6 && intel_rps_is_active(rps)) {
u32 rpup, rpupei; u32 rpup, rpupei;

4
drivers/gpu/drm/i915/i915_request.c
View file

@ -307,10 +307,8 @@ bool i915_request_retire(struct i915_request *rq)
spin_unlock_irq(&rq->lock); spin_unlock_irq(&rq->lock);
} }
if (i915_request_has_waitboost(rq)) { if (test_and_set_bit(I915_FENCE_FLAG_BOOST, &rq->fence.flags))
GEM_BUG_ON(!atomic_read(&rq->engine->gt->rps.num_waiters));
atomic_dec(&rq->engine->gt->rps.num_waiters); atomic_dec(&rq->engine->gt->rps.num_waiters);
}
/* /*
* We only loosely track inflight requests across preemption, * We only loosely track inflight requests across preemption,