[Intel-gfx] [PATCH 06/28] drm/i915/gt: Use virtual_engine during execlists_dequeue
Chris Wilson
chris at chris-wilson.co.uk
Sun Jun 7 22:20:46 UTC 2020
Rather than going back and forth between the rb_node entry and the
virtual_engine type, store the ve local and reuse it. As the
container_of conversion from rb_node to virtual_engine requires a
variable offset, performing that conversion just once shaves off a bit
of code.
v2: Keep a single virtual engine lookup, for typical use.
Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
---
drivers/gpu/drm/i915/gt/intel_lrc.c | 217 +++++++++++++---------------
1 file changed, 104 insertions(+), 113 deletions(-)
diff --git a/drivers/gpu/drm/i915/gt/intel_lrc.c b/drivers/gpu/drm/i915/gt/intel_lrc.c
index db8a170b0e5c..ab1f3131b357 100644
--- a/drivers/gpu/drm/i915/gt/intel_lrc.c
+++ b/drivers/gpu/drm/i915/gt/intel_lrc.c
@@ -454,7 +454,7 @@ static int queue_prio(const struct intel_engine_execlists *execlists)
static inline bool need_preempt(const struct intel_engine_cs *engine,
const struct i915_request *rq,
- struct rb_node *rb)
+ struct virtual_engine *ve)
{
int last_prio;
@@ -491,9 +491,7 @@ static inline bool need_preempt(const struct intel_engine_cs *engine,
rq_prio(list_next_entry(rq, sched.link)) > last_prio)
return true;
- if (rb) {
- struct virtual_engine *ve =
- rb_entry(rb, typeof(*ve), nodes[engine->id].rb);
+ if (ve) {
bool preempt = false;
if (engine == ve->siblings[0]) { /* only preempt one sibling */
@@ -1811,6 +1809,35 @@ static bool virtual_matches(const struct virtual_engine *ve,
return true;
}
+static struct virtual_engine *
+first_virtual_engine(struct intel_engine_cs *engine)
+{
+ struct intel_engine_execlists *el = &engine->execlists;
+ struct rb_node *rb = rb_first_cached(&el->virtual);
+
+ while (rb) {
+ struct virtual_engine *ve =
+ rb_entry(rb, typeof(*ve), nodes[engine->id].rb);
+ struct i915_request *rq = READ_ONCE(ve->request);
+
+ if (!rq) { /* lazily cleanup after another engine handled rq */
+ rb_erase_cached(rb, &el->virtual);
+ RB_CLEAR_NODE(rb);
+ rb = rb_first_cached(&el->virtual);
+ continue;
+ }
+
+ if (!virtual_matches(ve, rq, engine)) {
+ rb = rb_next(rb);
+ continue;
+ }
+
+ return ve;
+ }
+
+ return NULL;
+}
+
static void virtual_xfer_breadcrumbs(struct virtual_engine *ve)
{
/*
@@ -1895,7 +1922,7 @@ static void defer_active(struct intel_engine_cs *engine)
static bool
need_timeslice(const struct intel_engine_cs *engine,
const struct i915_request *rq,
- const struct rb_node *rb)
+ struct virtual_engine *ve)
{
int hint;
@@ -1904,9 +1931,7 @@ need_timeslice(const struct intel_engine_cs *engine,
hint = engine->execlists.queue_priority_hint;
- if (rb) {
- const struct virtual_engine *ve =
- rb_entry(rb, typeof(*ve), nodes[engine->id].rb);
+ if (ve) {
const struct intel_engine_cs *inflight =
intel_context_inflight(&ve->context);
@@ -2057,7 +2082,8 @@ static void execlists_dequeue(struct intel_engine_cs *engine)
struct intel_engine_execlists * const execlists = &engine->execlists;
struct i915_request **port = execlists->pending;
struct i915_request ** const last_port = port + execlists->port_mask;
- struct i915_request * const *active;
+ struct i915_request * const *active = READ_ONCE(execlists->active);
+ struct virtual_engine *ve = first_virtual_engine(engine);
struct i915_request *last;
struct rb_node *rb;
bool submit = false;
@@ -2084,26 +2110,6 @@ static void execlists_dequeue(struct intel_engine_cs *engine)
* and context switches) submission.
*/
- for (rb = rb_first_cached(&execlists->virtual); rb; ) {
- struct virtual_engine *ve =
- rb_entry(rb, typeof(*ve), nodes[engine->id].rb);
- struct i915_request *rq = READ_ONCE(ve->request);
-
- if (!rq) { /* lazily cleanup after another engine handled rq */
- rb_erase_cached(rb, &execlists->virtual);
- RB_CLEAR_NODE(rb);
- rb = rb_first_cached(&execlists->virtual);
- continue;
- }
-
- if (!virtual_matches(ve, rq, engine)) {
- rb = rb_next(rb);
- continue;
- }
-
- break;
- }
-
/*
* If the queue is higher priority than the last
* request in the currently active context, submit afresh.
@@ -2111,10 +2117,7 @@ static void execlists_dequeue(struct intel_engine_cs *engine)
* the active context to interject the preemption request,
* i.e. we will retrigger preemption following the ack in case
* of trouble.
- */
- active = READ_ONCE(execlists->active);
-
- /*
+ *
* In theory we can skip over completed contexts that have not
* yet been processed by events (as those events are in flight):
*
@@ -2125,9 +2128,8 @@ static void execlists_dequeue(struct intel_engine_cs *engine)
* find itself trying to jump back into a context it has just
* completed and barf.
*/
-
if ((last = *active)) {
- if (need_preempt(engine, last, rb)) {
+ if (need_preempt(engine, last, ve)) {
if (i915_request_completed(last)) {
tasklet_hi_schedule(&execlists->tasklet);
return;
@@ -2158,7 +2160,7 @@ static void execlists_dequeue(struct intel_engine_cs *engine)
__unwind_incomplete_requests(engine);
last = NULL;
- } else if (need_timeslice(engine, last, rb) &&
+ } else if (need_timeslice(engine, last, ve) &&
timeslice_expired(execlists, last)) {
if (i915_request_completed(last)) {
tasklet_hi_schedule(&execlists->tasklet);
@@ -2212,110 +2214,99 @@ static void execlists_dequeue(struct intel_engine_cs *engine)
}
}
- while (rb) { /* XXX virtual is always taking precedence */
- struct virtual_engine *ve =
- rb_entry(rb, typeof(*ve), nodes[engine->id].rb);
+ while (ve) { /* XXX virtual is always taking precedence */
struct i915_request *rq;
spin_lock(&ve->base.active.lock);
rq = ve->request;
- if (unlikely(!rq)) { /* lost the race to a sibling */
- spin_unlock(&ve->base.active.lock);
- rb_erase_cached(rb, &execlists->virtual);
- RB_CLEAR_NODE(rb);
- rb = rb_first_cached(&execlists->virtual);
- continue;
- }
+ if (unlikely(!rq)) /* lost the race to a sibling */
+ goto unlock;
GEM_BUG_ON(rq != ve->request);
GEM_BUG_ON(rq->engine != &ve->base);
GEM_BUG_ON(rq->context != &ve->context);
- if (rq_prio(rq) >= queue_prio(execlists)) {
- if (!virtual_matches(ve, rq, engine)) {
- spin_unlock(&ve->base.active.lock);
- rb = rb_next(rb);
- continue;
- }
+ if (unlikely(rq_prio(rq) < queue_prio(execlists))) {
+ spin_unlock(&ve->base.active.lock);
+ break;
+ }
- if (last && !can_merge_rq(last, rq)) {
- spin_unlock(&ve->base.active.lock);
- start_timeslice(engine, rq_prio(rq));
- return; /* leave this for another sibling */
- }
+ GEM_BUG_ON(!virtual_matches(ve, rq, engine));
- ENGINE_TRACE(engine,
- "virtual rq=%llx:%lld%s, new engine? %s\n",
- rq->fence.context,
- rq->fence.seqno,
- i915_request_completed(rq) ? "!" :
- i915_request_started(rq) ? "*" :
- "",
- yesno(engine != ve->siblings[0]));
-
- WRITE_ONCE(ve->request, NULL);
- WRITE_ONCE(ve->base.execlists.queue_priority_hint,
- INT_MIN);
- rb_erase_cached(rb, &execlists->virtual);
- RB_CLEAR_NODE(rb);
+ if (last && !can_merge_rq(last, rq)) {
+ spin_unlock(&ve->base.active.lock);
+ start_timeslice(engine, rq_prio(rq));
+ return; /* leave this for another sibling */
+ }
- GEM_BUG_ON(!(rq->execution_mask & engine->mask));
- WRITE_ONCE(rq->engine, engine);
+ ENGINE_TRACE(engine,
+ "virtual rq=%llx:%lld%s, new engine? %s\n",
+ rq->fence.context,
+ rq->fence.seqno,
+ i915_request_completed(rq) ? "!" :
+ i915_request_started(rq) ? "*" :
+ "",
+ yesno(engine != ve->siblings[0]));
- if (engine != ve->siblings[0]) {
- u32 *regs = ve->context.lrc_reg_state;
- unsigned int n;
+ WRITE_ONCE(ve->request, NULL);
+ WRITE_ONCE(ve->base.execlists.queue_priority_hint,
+ INT_MIN);
- GEM_BUG_ON(READ_ONCE(ve->context.inflight));
+ rb = &ve->nodes[engine->id].rb;
+ rb_erase_cached(rb, &execlists->virtual);
+ RB_CLEAR_NODE(rb);
- if (!intel_engine_has_relative_mmio(engine))
- virtual_update_register_offsets(regs,
- engine);
+ GEM_BUG_ON(!(rq->execution_mask & engine->mask));
+ WRITE_ONCE(rq->engine, engine);
- if (!list_empty(&ve->context.signals))
- virtual_xfer_breadcrumbs(ve);
+ if (engine != ve->siblings[0]) {
+ u32 *regs = ve->context.lrc_reg_state;
+ unsigned int n;
- /*
- * Move the bound engine to the top of the list
- * for future execution. We then kick this
- * tasklet first before checking others, so that
- * we preferentially reuse this set of bound
- * registers.
- */
- for (n = 1; n < ve->num_siblings; n++) {
- if (ve->siblings[n] == engine) {
- swap(ve->siblings[n],
- ve->siblings[0]);
- break;
- }
- }
+ GEM_BUG_ON(READ_ONCE(ve->context.inflight));
- GEM_BUG_ON(ve->siblings[0] != engine);
- }
+ if (!intel_engine_has_relative_mmio(engine))
+ virtual_update_register_offsets(regs,
+ engine);
- if (__i915_request_submit(rq)) {
- submit = true;
- last = rq;
- }
- i915_request_put(rq);
+ if (!list_empty(&ve->context.signals))
+ virtual_xfer_breadcrumbs(ve);
/*
- * Hmm, we have a bunch of virtual engine requests,
- * but the first one was already completed (thanks
- * preempt-to-busy!). Keep looking at the veng queue
- * until we have no more relevant requests (i.e.
- * the normal submit queue has higher priority).
+ * Move the bound engine to the top of the list for
+ * future execution. We then kick this tasklet first
+ * before checking others, so that we preferentially
+ * reuse this set of bound registers.
*/
- if (!submit) {
- spin_unlock(&ve->base.active.lock);
- rb = rb_first_cached(&execlists->virtual);
- continue;
+ for (n = 1; n < ve->num_siblings; n++) {
+ if (ve->siblings[n] == engine) {
+ swap(ve->siblings[n],
+ ve->siblings[0]);
+ break;
+ }
}
+
+ GEM_BUG_ON(ve->siblings[0] != engine);
}
+ if (__i915_request_submit(rq)) {
+ submit = true;
+ last = rq;
+ }
+
+ i915_request_put(rq);
+unlock:
spin_unlock(&ve->base.active.lock);
- break;
+
+ /*
+ * Hmm, we have a bunch of virtual engine requests,
+ * but the first one was already completed (thanks
+ * preempt-to-busy!). Keep looking at the veng queue
+ * until we have no more relevant requests (i.e.
+ * the normal submit queue has higher priority).
+ */
+ ve = submit ? NULL : first_virtual_engine(engine);
}
while ((rb = rb_first_cached(&execlists->queue))) {
--
2.20.1
More information about the Intel-gfx
mailing list