On 14/09/2017 21:22, Chris Wilson wrote:
Quoting Tvrtko Ursulin (2017-09-13 13:18:19)From: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx> This reduces the cost of the software engine busyness tracking to a single no-op instruction when there are no listeners. v2: Rebase and some comments. v3: Rebase. Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx> --- drivers/gpu/drm/i915/i915_pmu.c | 54 +++++++++++++++++++++++-- drivers/gpu/drm/i915/intel_engine_cs.c | 17 ++++++++ drivers/gpu/drm/i915/intel_ringbuffer.h | 70 ++++++++++++++++++++++----------- 3 files changed, 113 insertions(+), 28 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_pmu.c b/drivers/gpu/drm/i915/i915_pmu.c index 3c0c5d0549b3..d734879e67ee 100644 --- a/drivers/gpu/drm/i915/i915_pmu.c +++ b/drivers/gpu/drm/i915/i915_pmu.c @@ -460,11 +460,17 @@ static void i915_pmu_enable(struct perf_event *event) GEM_BUG_ON(sample >= I915_PMU_SAMPLE_BITS); GEM_BUG_ON(engine->pmu.enable_count[sample] == ~0); if (engine->pmu.enable_count[sample]++ == 0) { + /* + * Enable engine busy stats tracking if needed or + * alternatively cancel the scheduled disabling of the + * same. + */ if (engine_needs_busy_stats(engine) && !engine->pmu.busy_stats) { - engine->pmu.busy_stats = - intel_enable_engine_stats(engine) == 0; - WARN_ON_ONCE(!engine->pmu.busy_stats); + engine->pmu.busy_stats = true; + if (!cancel_delayed_work(&engine->pmu.disable_busy_stats)) + queue_work(i915->wq, + &engine->pmu.enable_busy_stats);The only users of i915->wq are supposed to be dependent on struct_mutex, it is limited to a single job under the presumption that each worker would be serialised by that mutex.
Good point, so I need a dedicated wq. Might still want to make it ordered since they themselves will be serialised by the global static key mutex.
Regards, Tvrtko _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
