Commit dc93c9b6 authored by Chris Wilson's avatar Chris Wilson
Browse files

drm/i915/gt: Schedule request retirement when signaler idles 



Very similar to commit 4f88f874 ("drm/i915/gt: Schedule request
retirement when timeline idles"), but this time instead of coupling into
the execlists CS event interrupt, we couple into the breadcrumb
interrupt and queue a timeline's retirement when the last signaler is
completed. This should allow us to more rapidly park ringbuffer
submission, and so help reduce power consumption on older systems.

v2: Fixup intel_engine_add_retire() to handle concurrent callers

References: 4f88f874 ("drm/i915/gt: Schedule request retirement when timeline idles")
Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: default avatarJoonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191219124353.8607-1-chris@chris-wilson.co.uk
parent cabeacd4

drivers/gpu/drm/i915/gt/intel_breadcrumbs.c

+5 −1
Original line number Diff line number Diff line
@@ -29,6 +29,7 @@ 
#include "i915_drv.h"

#include "i915_trace.h"

#include "intel_gt_pm.h"

#include "intel_gt_requests.h"



static void irq_enable(struct intel_engine_cs *engine)

{
@@ -179,8 +180,11 @@ static void signal_irq_work(struct irq_work *work) 
		if (!list_is_first(pos, &ce->signals)) {

			/* Advance the list to the first incomplete request */

			__list_del_many(&ce->signals, pos);

			if (&ce->signals == pos) /* now empty */

			if (&ce->signals == pos) { /* now empty */

				list_del_init(&ce->signal_link);

				intel_engine_add_retire(ce->engine,

							ce->timeline);

			}

		}

	}

drivers/gpu/drm/i915/gt/intel_gt_requests.c

+2 −5
Original line number Diff line number Diff line
@@ -62,19 +62,16 @@ static void engine_retire(struct work_struct *work) 
static bool add_retire(struct intel_engine_cs *engine,

		       struct intel_timeline *tl)

{

#define STUB ((struct intel_timeline *)1)

	struct intel_timeline *first;



	/*

	 * We open-code a llist here to include the additional tag [BIT(0)]

	 * so that we know when the timeline is already on a

	 * retirement queue: either this engine or another.

	 *

	 * However, we rely on that a timeline can only be active on a single

	 * engine at any one time and that add_retire() is called before the

	 * engine releases the timeline and transferred to another to retire.

	 */



	if (READ_ONCE(tl->retire)) /* already queued */

	if (cmpxchg(&tl->retire, NULL, STUB)) /* already queued */

		return false;



	intel_timeline_get(tl);

drivers/gpu/drm/i915/gt/intel_lrc.c

+1 −1
Original line number Diff line number Diff line
@@ -4511,8 +4511,8 @@ intel_execlists_create_virtual(struct i915_gem_context *ctx, 


	intel_engine_init_active(&ve->base, ENGINE_VIRTUAL);

	intel_engine_init_breadcrumbs(&ve->base);



	intel_engine_init_execlists(&ve->base);

	intel_engine_init_retire(&ve->base);



	ve->base.cops = &virtual_context_ops;

	ve->base.request_alloc = execlists_request_alloc;

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