From: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx>
Assorted changes most likely without any practical effect
apart from a tiny reduction in generated code for the interrupt
handler and request submission.
* Remove needless initialization.
* Improve cache locality by reorganizing code and/or using
branch hints to keep unexpected or error conditions out
of line.
* Favor busy submit path vs. empty queue.
* Less branching in hot-paths.
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx>
---
drivers/gpu/drm/i915/intel_lrc.c | 91 ++++++++++++++++-----------------
drivers/gpu/drm/i915/intel_ringbuffer.h | 1 +
2 files changed, 44 insertions(+), 48 deletions(-)
diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
index 951f1e6af947..589d6404b5ca 100644
--- a/drivers/gpu/drm/i915/intel_lrc.c
+++ b/drivers/gpu/drm/i915/intel_lrc.c
@@ -269,6 +269,9 @@ logical_ring_init_platform_invariants(struct intel_engine_cs *ring)
{
struct drm_device *dev = ring->dev;
+ if (IS_GEN8(dev) || IS_GEN9(dev))
+ ring->idle_lite_restore_wa = ~0;
+
ring->disable_lite_restore_wa = (IS_SKL_REVID(dev, 0, SKL_REVID_B0) ||
IS_BXT_REVID(dev, 0, BXT_REVID_A1)) &&
(ring->id == VCS || ring->id == VCS2);
@@ -424,7 +427,7 @@ static void execlists_submit_requests(struct drm_i915_gem_request *rq0,
static void execlists_context_unqueue(struct intel_engine_cs *ring)
{
struct drm_i915_gem_request *req0 = NULL, *req1 = NULL;
- struct drm_i915_gem_request *cursor = NULL, *tmp = NULL;
+ struct drm_i915_gem_request *cursor, *tmp;
assert_spin_locked(&ring->execlist_lock);
@@ -434,9 +437,6 @@ static void execlists_context_unqueue(struct intel_engine_cs *ring)
*/
WARN_ON(!intel_irqs_enabled(ring->dev->dev_private));
- if (list_empty(&ring->execlist_queue))
- return;
-
/* Try to read in pairs */
list_for_each_entry_safe(cursor, tmp, &ring->execlist_queue,
execlist_link) {
@@ -451,37 +451,35 @@ static void execlists_context_unqueue(struct intel_engine_cs *ring)
req0 = cursor;
} else {
req1 = cursor;
+ WARN_ON(req1->elsp_submitted);
break;
}
}
- if (IS_GEN8(ring->dev) || IS_GEN9(ring->dev)) {
+ if (unlikely(!req0))
+ return;
+
+ if (req0->elsp_submitted & ring->idle_lite_restore_wa) {
/*
- * WaIdleLiteRestore: make sure we never cause a lite
- * restore with HEAD==TAIL
+ * WaIdleLiteRestore: make sure we never cause a lite restore
+ * with HEAD==TAIL.
+ *
+ * Apply the wa NOOPS to prevent ring:HEAD == req:TAIL as we
+ * resubmit the request. See gen8_emit_request() for where we
+ * prepare the padding after the end of the request.
*/
- if (req0->elsp_submitted) {
- /*
- * Apply the wa NOOPS to prevent ring:HEAD == req:TAIL
- * as we resubmit the request. See gen8_emit_request()
- * for where we prepare the padding after the end of the
- * request.
- */
- struct intel_ringbuffer *ringbuf;
+ struct intel_ringbuffer *ringbuf;
- ringbuf = req0->ctx->engine[ring->id].ringbuf;
- req0->tail += 8;
- req0->tail &= ringbuf->size - 1;
- }
+ ringbuf = req0->ctx->engine[ring->id].ringbuf;
+ req0->tail += 8;
+ req0->tail &= ringbuf->size - 1;
}
- WARN_ON(req1 && req1->elsp_submitted);
-
execlists_submit_requests(req0, req1);
}
-static bool execlists_check_remove_request(struct intel_engine_cs *ring,
- u32 request_id)
+static unsigned int
+execlists_check_remove_request(struct intel_engine_cs *ring, u32 request_id)
{
struct drm_i915_gem_request *head_req;
@@ -491,20 +489,21 @@ static bool execlists_check_remove_request(struct intel_engine_cs *ring,
struct drm_i915_gem_request,
execlist_link);
- if (head_req != NULL) {
- if (intel_execlists_ctx_id(head_req->ctx, ring) == request_id) {
- WARN(head_req->elsp_submitted == 0,
- "Never submitted head request\n");
+ if (!head_req)
+ return 0;
+
+ if (unlikely(intel_execlists_ctx_id(head_req->ctx, ring) != request_id))
+ return 0;
- if (--head_req->elsp_submitted <= 0) {
- list_move_tail(&head_req->execlist_link,
- &ring->execlist_retired_req_list);
- return true;
- }
- }
- }
+ WARN(head_req->elsp_submitted == 0, "Never submitted head request\n");
- return false;
+ if (--head_req->elsp_submitted > 0)
+ return 0;
+
+ list_move_tail(&head_req->execlist_link,
+ &ring->execlist_retired_req_list);
+
+ return 1;
}
static u32 get_context_status(struct intel_engine_cs *ring, u8 read_pointer,
@@ -551,7 +550,7 @@ void intel_lrc_irq_handler(struct intel_engine_cs *ring)
if (status & GEN8_CTX_STATUS_IDLE_ACTIVE)
continue;
- if (status & GEN8_CTX_STATUS_PREEMPTED) {
+ if (unlikely(status & GEN8_CTX_STATUS_PREEMPTED)) {
if (status & GEN8_CTX_STATUS_LITE_RESTORE) {
if (execlists_check_remove_request(ring, status_id))
WARN(1, "Lite Restored request removed from queue\n");
@@ -559,21 +558,16 @@ void intel_lrc_irq_handler(struct intel_engine_cs *ring)
WARN(1, "Preemption without Lite Restore\n");
}
- if ((status & GEN8_CTX_STATUS_ACTIVE_IDLE) ||
- (status & GEN8_CTX_STATUS_ELEMENT_SWITCH)) {
- if (execlists_check_remove_request(ring, status_id))
- submit_contexts++;
- }
+ if (status & (GEN8_CTX_STATUS_ACTIVE_IDLE |
+ GEN8_CTX_STATUS_ELEMENT_SWITCH))
+ submit_contexts +=
+ execlists_check_remove_request(ring, status_id);
}
- if (ring->disable_lite_restore_wa) {
- /* Prevent a ctx to preempt itself */
- if ((status & GEN8_CTX_STATUS_ACTIVE_IDLE) &&
- (submit_contexts != 0))
- execlists_context_unqueue(ring);
- } else if (submit_contexts != 0) {
+ if (submit_contexts && (!ring->disable_lite_restore_wa ||
+ (ring->disable_lite_restore_wa && (status &
+ GEN8_CTX_STATUS_ACTIVE_IDLE))))
execlists_context_unqueue(ring);
- }
spin_unlock(&ring->execlist_lock);
@@ -2028,6 +2022,7 @@ void intel_logical_ring_cleanup(struct intel_engine_cs *ring)
ring->status_page.obj = NULL;
}
+ ring->idle_lite_restore_wa = 0;
ring->disable_lite_restore_wa = false;
ring->ctx_desc_template = 0;
diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.h b/drivers/gpu/drm/i915/intel_ringbuffer.h
index 566b0ae10ce0..54054ba6e223 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.h
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.h
@@ -272,6 +272,7 @@ struct intel_engine_cs {
struct list_head execlist_queue;
struct list_head execlist_retired_req_list;
u8 next_context_status_buffer;
+ unsigned int idle_lite_restore_wa;
bool disable_lite_restore_wa;
u32 ctx_desc_template;
u32 irq_keep_mask; /* bitmask for interrupts that should not be masked */
--
1.9.1
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