@@ -1052,8 +1052,20 @@ 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 */
@@ -19,12 +19,14 @@ enum {
I915_PRIORITY_INVALID = INT_MIN
};
-#define I915_USER_PRIORITY_SHIFT 0
+#define I915_USER_PRIORITY_SHIFT 1
#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)
+#define I915_PRIORITY_NEWCLIENT BIT(0)
+
struct i915_sched_attr {
/**
* @priority: execution and service priority
Taken from an idea used for FQ_CODEL, we give new request flows a priority boost. These flows are likely to correspond with interactive tasks and so be more latency sensitive than the long 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). 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> --- drivers/gpu/drm/i915/i915_request.c | 16 ++++++++++++++-- drivers/gpu/drm/i915/i915_scheduler.h | 4 +++- 2 files changed, 17 insertions(+), 3 deletions(-)