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Commit 91d0101a authored by Ping Gao's avatar Ping Gao Committed by Zhenyu Wang
Browse files

drm/i915/gvt: use hrtimer replace delayed_work in scheduler 



Currently the scheduler is triggered by delayed_work, which doesn't
provide precision at microsecond level. Move to hrtimer instead for
more accurate control.

Signed-off-by: default avatarPing Gao <ping.a.gao@intel.com>
Reviewed-by: default avatarKevin Tian <kevin.tian@intel.com>
Signed-off-by: default avatarZhenyu Wang <zhenyuw@linux.intel.com>
parent 865f03d4

drivers/gpu/drm/i915/gvt/gvt.c

+5 −0
Original line number Diff line number Diff line
@@ -144,6 +144,11 @@ static int gvt_service_thread(void *data) 
			intel_gvt_emulate_vblank(gvt);

			mutex_unlock(&gvt->lock);

		}



		if (test_and_clear_bit(INTEL_GVT_REQUEST_SCHED,

					(void *)&gvt->service_request)) {

			intel_gvt_schedule(gvt);

		}

	}



	return 0;

drivers/gpu/drm/i915/gvt/gvt.h

+1 −0
Original line number Diff line number Diff line
@@ -249,6 +249,7 @@ static inline struct intel_gvt *to_gvt(struct drm_i915_private *i915) 


enum {

	INTEL_GVT_REQUEST_EMULATE_VBLANK = 0,

	INTEL_GVT_REQUEST_SCHED = 1,

};



static inline void intel_gvt_request_service(struct intel_gvt *gvt,

drivers/gpu/drm/i915/gvt/sched_policy.c

+33 −16
Original line number Diff line number Diff line
@@ -96,17 +96,16 @@ struct tbs_vgpu_data { 


struct tbs_sched_data {

	struct intel_gvt *gvt;

	struct delayed_work work;

	struct hrtimer timer;

	unsigned long period;

	struct list_head runq_head;

};



#define GVT_DEFAULT_TIME_SLICE (msecs_to_jiffies(1))

/* in nanosecond */

#define GVT_DEFAULT_TIME_SLICE 1000000



static void tbs_sched_func(struct work_struct *work)

static void tbs_sched_func(struct tbs_sched_data *sched_data)

{

	struct tbs_sched_data *sched_data = container_of(work,

			struct tbs_sched_data, work.work);

	struct tbs_vgpu_data *vgpu_data;



	struct intel_gvt *gvt = sched_data->gvt;
@@ -115,8 +114,6 @@ static void tbs_sched_func(struct work_struct *work) 
	struct intel_vgpu *vgpu = NULL;

	struct list_head *pos, *head;



	mutex_lock(&gvt->lock);



	/* no vgpu or has already had a target */

	if (list_empty(&sched_data->runq_head) || scheduler->next_vgpu)

		goto out;
@@ -151,17 +148,30 @@ static void tbs_sched_func(struct work_struct *work) 
				scheduler->next_vgpu->id);

		try_to_schedule_next_vgpu(gvt);

	}

}



	/*

	 * still have vgpu on runq

	 * or last schedule haven't finished due to running workload

	 */

	if (!list_empty(&sched_data->runq_head) || scheduler->next_vgpu)

		schedule_delayed_work(&sched_data->work, sched_data->period);

void intel_gvt_schedule(struct intel_gvt *gvt)

{

	struct tbs_sched_data *sched_data = gvt->scheduler.sched_data;



	mutex_lock(&gvt->lock);

	tbs_sched_func(sched_data);

	mutex_unlock(&gvt->lock);

}



static enum hrtimer_restart tbs_timer_fn(struct hrtimer *timer_data)

{

	struct tbs_sched_data *data;



	data = container_of(timer_data, struct tbs_sched_data, timer);



	intel_gvt_request_service(data->gvt, INTEL_GVT_REQUEST_SCHED);



	hrtimer_add_expires_ns(&data->timer, data->period);



	return HRTIMER_RESTART;

}



static int tbs_sched_init(struct intel_gvt *gvt)

{

	struct intel_gvt_workload_scheduler *scheduler =
@@ -174,11 +184,13 @@ static int tbs_sched_init(struct intel_gvt *gvt) 
		return -ENOMEM;



	INIT_LIST_HEAD(&data->runq_head);

	INIT_DELAYED_WORK(&data->work, tbs_sched_func);

	hrtimer_init(&data->timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS);

	data->timer.function = tbs_timer_fn;

	data->period = GVT_DEFAULT_TIME_SLICE;

	data->gvt = gvt;



	scheduler->sched_data = data;



	return 0;

}
@@ -188,7 +200,8 @@ static void tbs_sched_clean(struct intel_gvt *gvt) 
		&gvt->scheduler;

	struct tbs_sched_data *data = scheduler->sched_data;



	cancel_delayed_work(&data->work);

	hrtimer_cancel(&data->timer);



	kfree(data);

	scheduler->sched_data = NULL;

}
@@ -205,6 +218,7 @@ static int tbs_sched_init_vgpu(struct intel_vgpu *vgpu) 
	INIT_LIST_HEAD(&data->list);



	vgpu->sched_data = data;



	return 0;

}
@@ -223,7 +237,10 @@ static void tbs_sched_start_schedule(struct intel_vgpu *vgpu) 
		return;



	list_add_tail(&vgpu_data->list, &sched_data->runq_head);

	schedule_delayed_work(&sched_data->work, 0);



	if (!hrtimer_active(&sched_data->timer))

		hrtimer_start(&sched_data->timer, ktime_add_ns(ktime_get(),

			sched_data->period), HRTIMER_MODE_ABS);

}



static void tbs_sched_stop_schedule(struct intel_vgpu *vgpu)

drivers/gpu/drm/i915/gvt/sched_policy.h

+2 −0
Original line number Diff line number Diff line
@@ -43,6 +43,8 @@ struct intel_gvt_sched_policy_ops { 
	void (*stop_schedule)(struct intel_vgpu *vgpu);

};



void intel_gvt_schedule(struct intel_gvt *gvt);



int intel_gvt_init_sched_policy(struct intel_gvt *gvt);



void intel_gvt_clean_sched_policy(struct intel_gvt *gvt);