From 6277c8d07b8f1b667f672628f88b18e831e67517 Mon Sep 17 00:00:00 2001 From: Imre Deak Date: Tue, 20 Sep 2016 14:58:19 +0300 Subject: [PATCH] drm/i915: Queue page flip work via a low latency, unbound workqueue While user space has control over the scheduling priority of its page flipping thread, the corresponding work the driver schedules for MMIO flips always runs from the generic system workqueue which has some scheduling overhead due it being CPU bound. This would hinder an application that wants more stringent guarantees over flip timing (to avoid missing a flip at the next frame count). Fix this by scheduling the work from the unbound system workqueue which provides for minimal scheduling latency. v2: - Use an unbound workqueue instead of a high-prio one. (Tvrtko, Chris) v3: - Use the system unbound wq instead of a dedicated one. (Maarten) Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=97775 Testcase: igt/kms_cursor_legacy CC: Chris Wilson CC: Maarten Lankhorst CC: Tvrtko Ursulin Signed-off-by: Imre Deak Reviewed-by: Tvrtko Ursulin (v1) Reviewed-by: Chris Wilson Reviewed-by: Maarten Lankhorst Link: http://patchwork.freedesktop.org/patch/msgid/1474372699-22841-1-git-send-email-imre.deak@intel.com --- drivers/gpu/drm/i915/intel_display.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c index 18fdbb7..f7b2f8f 100644 --- a/drivers/gpu/drm/i915/intel_display.c +++ b/drivers/gpu/drm/i915/intel_display.c @@ -12266,7 +12266,7 @@ static int intel_crtc_page_flip(struct drm_crtc *crtc, work->flip_queued_req = i915_gem_active_get(&obj->last_write, &obj->base.dev->struct_mutex); - schedule_work(&work->mmio_work); + queue_work(system_unbound_wq, &work->mmio_work); } else { request = i915_gem_request_alloc(engine, engine->last_context); if (IS_ERR(request)) { -- 2.7.4