[PATCH 3/3] drm/i915/execlists: Cache the last priolist lookup

Chris Wilson
2017-09-25T12:49:40Z

From: Michał Winiarski <michal.winiarski@intel.com>

Avoid the repeated rbtree lookup for each request as we unwind them by
tracking the last priolist.

Signed-off-by: Michał Winiarski <michal.winiarski@intel.com>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
---
drivers/gpu/drm/i915/intel_lrc.c | 18 ++++++++++++------
1 file changed, 12 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
index c84831c7ea4a..7802b1bd2b5c 100644
--- a/drivers/gpu/drm/i915/intel_lrc.c
+++ b/drivers/gpu/drm/i915/intel_lrc.c
@@ -357,13 +357,14 @@ static void unwind_wa_tail(struct drm_i915_gem_request *rq)

static void unwind_incomplete_requests(struct intel_engine_cs *engine)
{
+ struct i915_priolist *p = &engine->execlists.default_priolist;
+ int last_prio = I915_PRIORITY_NORMAL;
struct drm_i915_gem_request *rq, *rn;

lockdep_assert_held(&engine->timeline->lock);
list_for_each_entry_safe_reverse(rq, rn,
&engine->timeline->requests,
link) {
- struct i915_priolist *p;

if (i915_gem_request_completed(rq))
return;
@@ -371,11 +372,16 @@ static void unwind_incomplete_requests(struct intel_engine_cs *engine)
__i915_gem_request_unsubmit(rq);
unwind_wa_tail(rq);

- p = lookup_priolist(engine,
- &rq->priotree,
- rq->priotree.priority);
- list_add(&rq->priotree.link,
- &ptr_mask_bits(p, 1)->requests);
+ if (rq->priotree.priority != last_prio) {
+ p = lookup_priolist(engine,
+ &rq->priotree,
+ rq->priotree.priority);
+ p = ptr_mask_bits(p, 1);
+
+ last_prio = rq->priotree.priority;
+ }
+
+ list_add(&rq->priotree.link, &p->requests);
}
}

--
2.14.1