On 27/02/2020 08:57, Chris Wilson wrote:
Let userspace know if they can trust timeslicing by including it as part
of the I915_PARAM_HAS_SCHEDULER::I915_SCHEDULER_CAP_TIMESLICING
v2: Only declare timeslicing if we can safely preempt userspace.
Fixes: 8ee36e048c98 ("drm/i915/execlists: Minimalistic timeslicing")
Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Cc: Kenneth Graunke <kenneth@xxxxxxxxxxxxx>
---
drivers/gpu/drm/i915/gt/intel_engine.h | 3 ++-
drivers/gpu/drm/i915/gt/intel_engine_user.c | 5 +++++
include/uapi/drm/i915_drm.h | 1 +
3 files changed, 8 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/i915/gt/intel_engine.h b/drivers/gpu/drm/i915/gt/intel_engine.h
index 29c8c03c5caa..a32dc82a90d4 100644
--- a/drivers/gpu/drm/i915/gt/intel_engine.h
+++ b/drivers/gpu/drm/i915/gt/intel_engine.h
@@ -326,7 +326,8 @@ intel_engine_has_timeslices(const struct intel_engine_cs *engine)
if (!IS_ACTIVE(CONFIG_DRM_I915_TIMESLICE_DURATION))
return false;
- return intel_engine_has_semaphores(engine);
+ return (intel_engine_has_semaphores(engine) &&
+ intel_engine_has_preemption(engine));
This could be the fixes bit.
AFAIR has_semaphores is can we preempt between batches and
has_preemption is can we preempt inside them. What was the consequence
of not considering this in has_timeslices?
}
#endif /* _INTEL_RINGBUFFER_H_ */
diff --git a/drivers/gpu/drm/i915/gt/intel_engine_user.c b/drivers/gpu/drm/i915/gt/intel_engine_user.c
index 848decee9066..b84fdd722781 100644
--- a/drivers/gpu/drm/i915/gt/intel_engine_user.c
+++ b/drivers/gpu/drm/i915/gt/intel_engine_user.c
@@ -121,6 +121,11 @@ static void set_scheduler_caps(struct drm_i915_private *i915)
else
disabled |= BIT(map[i].sched);
}
+
+ if (intel_engine_has_timeslices(engine))
+ enabled |= I915_SCHEDULER_CAP_TIMESLICING;
+ else
+ disabled |= I915_SCHEDULER_CAP_TIMESLICING;
}
i915->caps.scheduler = enabled & ~disabled;
diff --git a/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h
index 2813e579b480..4f903431a3fe 100644
--- a/include/uapi/drm/i915_drm.h
+++ b/include/uapi/drm/i915_drm.h
@@ -523,6 +523,7 @@ typedef struct drm_i915_irq_wait {
#define I915_SCHEDULER_CAP_PREEMPTION (1ul << 2)
#define I915_SCHEDULER_CAP_SEMAPHORES (1ul << 3)
#define I915_SCHEDULER_CAP_ENGINE_BUSY_STATS (1ul << 4)
+#define I915_SCHEDULER_CAP_TIMESLICING (1ul << 5)
And this would be the new uapi bit.
Split into two patches?
Regards,
Tvrtko
#define I915_PARAM_HUC_STATUS 42
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