drm/i915: Sleep whilst waiting for the ring
If userspace is submitting so many long running batches that the ring
becomes full, throttle by sleeping for a 1ms before checking for free
space. Simply yielding was causing excessive scheduler overhead whilst
making no progress.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
index d89b887..89004a6 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.c
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
@@ -707,7 +707,7 @@
master_priv->sarea_priv->perf_boxes |= I915_BOX_WAIT;
}
- yield();
+ msleep(1);
} while (!time_after(jiffies, end));
trace_i915_ring_wait_end (dev);
return -EBUSY;