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authorChris Wilson2018-10-01 16:47:53 +0200
committerChris Wilson2018-10-01 21:34:19 +0200
commitb16c765122f987056e1dc9ef6c214571bb5bd694 (patch)
tree4d40534af04067fbe590fbc25e0d6d221e3f7aa3 /drivers/gpu/drm/i915/i915_request.c
parentdrm/i915: Pass intel_encoder to infoframe functions (diff)
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drm/i915: Priority boost for new clients
Taken from an idea used for FQ_CODEL, we give the first request of a new request flows a small priority boost. These flows are likely to correspond with short, interactive tasks and so be more latency sensitive than the longer free running queues. As soon as the client has more than one request in the queue, further requests are not boosted and it settles down into ordinary steady state behaviour. Such small kicks dramatically help combat the starvation issue, by allowing each client the opportunity to run even when the system is under heavy throughput load (within the constraints of the user selected priority). v2: Mark the preempted request as the start of a new flow, to prevent a single client being continually gazumped by its peers. Testcase: igt/benchmarks/rrul Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20181001144755.7978-1-chris@chris-wilson.co.uk
Diffstat (limited to 'drivers/gpu/drm/i915/i915_request.c')
-rw-r--r--drivers/gpu/drm/i915/i915_request.c16
1 files changed, 14 insertions, 2 deletions
diff --git a/drivers/gpu/drm/i915/i915_request.c b/drivers/gpu/drm/i915/i915_request.c
index a492385b2089..56140ca054e8 100644
--- a/drivers/gpu/drm/i915/i915_request.c
+++ b/drivers/gpu/drm/i915/i915_request.c
@@ -1127,8 +1127,20 @@ void i915_request_add(struct i915_request *request)
*/
local_bh_disable();
rcu_read_lock(); /* RCU serialisation for set-wedged protection */
- if (engine->schedule)
- engine->schedule(request, &request->gem_context->sched);
+ if (engine->schedule) {
+ struct i915_sched_attr attr = request->gem_context->sched;
+
+ /*
+ * Boost priorities to new clients (new request flows).
+ *
+ * Allow interactive/synchronous clients to jump ahead of
+ * the bulk clients. (FQ_CODEL)
+ */
+ if (!prev || i915_request_completed(prev))
+ attr.priority |= I915_PRIORITY_NEWCLIENT;
+
+ engine->schedule(request, &attr);
+ }
rcu_read_unlock();
i915_sw_fence_commit(&request->submit);
local_bh_enable(); /* Kick the execlists tasklet if just scheduled */