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-rw-r--r--drivers/gpu/drm/i915/i915_request.c16
-rw-r--r--drivers/gpu/drm/i915/i915_scheduler.c6
-rw-r--r--drivers/gpu/drm/i915/i915_scheduler.h9
-rw-r--r--drivers/gpu/drm/i915/intel_lrc.c2
4 files changed, 29 insertions, 4 deletions
diff --git a/drivers/gpu/drm/i915/i915_request.c b/drivers/gpu/drm/i915/i915_request.c
index 59e30b8c4ee9..bcf3c1a155e2 100644
--- a/drivers/gpu/drm/i915/i915_request.c
+++ b/drivers/gpu/drm/i915/i915_request.c
@@ -813,6 +813,7 @@ emit_semaphore_wait(struct i915_request *to,
*cs++ = 0;
intel_ring_advance(to, cs);
+ to->sched.flags |= I915_SCHED_HAS_SEMAPHORE;
return 0;
}
@@ -1084,6 +1085,21 @@ void i915_request_add(struct i915_request *request)
struct i915_sched_attr attr = request->gem_context->sched;
/*
+ * Boost actual workloads past semaphores!
+ *
+ * With semaphores we spin on one engine waiting for another,
+ * simply to reduce the latency of starting our work when
+ * the signaler completes. However, if there is any other
+ * work that we could be doing on this engine instead, that
+ * is better utilisation and will reduce the overall duration
+ * of the current work. To avoid PI boosting a semaphore
+ * far in the distance past over useful work, we keep a history
+ * of any semaphore use along our dependency chain.
+ */
+ if (!(request->sched.flags & I915_SCHED_HAS_SEMAPHORE))
+ attr.priority |= I915_PRIORITY_NOSEMAPHORE;
+
+ /*
* Boost priorities to new clients (new request flows).
*
* Allow interactive/synchronous clients to jump ahead of
diff --git a/drivers/gpu/drm/i915/i915_scheduler.c b/drivers/gpu/drm/i915/i915_scheduler.c
index 50018ad30233..3f0a4d56bd37 100644
--- a/drivers/gpu/drm/i915/i915_scheduler.c
+++ b/drivers/gpu/drm/i915/i915_scheduler.c
@@ -39,6 +39,7 @@ void i915_sched_node_init(struct i915_sched_node *node)
INIT_LIST_HEAD(&node->waiters_list);
INIT_LIST_HEAD(&node->link);
node->attr.priority = I915_PRIORITY_INVALID;
+ node->flags = 0;
}
static struct i915_dependency *
@@ -69,6 +70,11 @@ bool __i915_sched_node_add_dependency(struct i915_sched_node *node,
dep->signaler = signal;
dep->flags = flags;
+ /* Keep track of whether anyone on this chain has a semaphore */
+ if (signal->flags & I915_SCHED_HAS_SEMAPHORE &&
+ !node_started(signal))
+ node->flags |= I915_SCHED_HAS_SEMAPHORE;
+
ret = true;
}
diff --git a/drivers/gpu/drm/i915/i915_scheduler.h b/drivers/gpu/drm/i915/i915_scheduler.h
index 7d4a49750d92..6ce450cf63fa 100644
--- a/drivers/gpu/drm/i915/i915_scheduler.h
+++ b/drivers/gpu/drm/i915/i915_scheduler.h
@@ -24,14 +24,15 @@ enum {
I915_PRIORITY_INVALID = INT_MIN
};
-#define I915_USER_PRIORITY_SHIFT 2
+#define I915_USER_PRIORITY_SHIFT 3
#define I915_USER_PRIORITY(x) ((x) << I915_USER_PRIORITY_SHIFT)
#define I915_PRIORITY_COUNT BIT(I915_USER_PRIORITY_SHIFT)
#define I915_PRIORITY_MASK (I915_PRIORITY_COUNT - 1)
-#define I915_PRIORITY_WAIT ((u8)BIT(0))
-#define I915_PRIORITY_NEWCLIENT ((u8)BIT(1))
+#define I915_PRIORITY_WAIT ((u8)BIT(0))
+#define I915_PRIORITY_NEWCLIENT ((u8)BIT(1))
+#define I915_PRIORITY_NOSEMAPHORE ((u8)BIT(2))
#define __NO_PREEMPTION (I915_PRIORITY_WAIT)
@@ -74,6 +75,8 @@ struct i915_sched_node {
struct list_head waiters_list; /* those after us, they depend upon us */
struct list_head link;
struct i915_sched_attr attr;
+ unsigned int flags;
+#define I915_SCHED_HAS_SEMAPHORE BIT(0)
};
struct i915_dependency {
diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
index 6c9479acb433..578c8c98c718 100644
--- a/drivers/gpu/drm/i915/intel_lrc.c
+++ b/drivers/gpu/drm/i915/intel_lrc.c
@@ -164,7 +164,7 @@
#define WA_TAIL_DWORDS 2
#define WA_TAIL_BYTES (sizeof(u32) * WA_TAIL_DWORDS)
-#define ACTIVE_PRIORITY (I915_PRIORITY_NEWCLIENT)
+#define ACTIVE_PRIORITY (I915_PRIORITY_NEWCLIENT | I915_PRIORITY_NOSEMAPHORE)
static int execlists_context_deferred_alloc(struct i915_gem_context *ctx,
struct intel_engine_cs *engine,