Quoting Tvrtko Ursulin (2021-06-01 11:24:00)

On 01/06/2021 11:10, Surendrakumar Upadhyay, TejaskumarX wrote:

quoted

quoted

-----Original Message-----
From: Tvrtko Ursulin <redacted>
Sent: 01 June 2021 15:38
To: Surendrakumar Upadhyay, TejaskumarX
[off-list ref]; igt-
dev@lists.freedesktop.org
Subject: Re: [igt-dev] [i-g-t V3 1/2] lib/i915: find scheduler caps for timeslicing


On 31/05/2021 14:41, Tejas Upadhyay wrote:

quoted

Check scheduler capability for timeslicing in appropriate way, which
requires wrappers to be created for IGT.

V3:
      removed conditional error - petri
V2: has_timeslice = has_semaphore && has_preemption ||
      has_guc_submission - Tvrtko

Signed-off-by: Tejas Upadhyay
[off-list ref]
---
   lib/i915/gem_scheduler.c | 21 +++++++++++++++++++++
   lib/i915/gem_scheduler.h |  1 +
   2 files changed, 22 insertions(+)

diff --git a/lib/i915/gem_scheduler.c b/lib/i915/gem_scheduler.c index

184da843..f59c451f 100644

--- a/lib/i915/gem_scheduler.c
+++ b/lib/i915/gem_scheduler.c

@@ -29,6 +29,7 @@
   #include "ioctl_wrappers.h"

   #include "i915/gem_scheduler.h"
+#include "i915/gem_submission.h"

   /**
    * SECTION:gem_scheduler

@@ -129,6 +130,22 @@ bool gem_scheduler_has_engine_busy_stats(int

fd)

quoted

            I915_SCHEDULER_CAP_ENGINE_BUSY_STATS;
   }

+/**
+ * gem_scheduler_has_timeslicing:
+ * @fd: open i915 drm file descriptor
+ *
+ * Feature test macro to query whether the driver supports using HW
+preemption
+ * to implement timeslicing of userspace batches. This allows
+userspace to
+ * implement micro-level scheduling within their own batches.
+ */
+bool gem_scheduler_has_timeslicing(int fd) {
+   return ((gem_scheduler_capability(fd) &
+           (I915_SCHEDULER_CAP_PREEMPTION |
+            I915_SCHEDULER_CAP_SEMAPHORES))

This bitwise or is incorrect, both are required.

quoted

quoted

quoted

+           || gem_has_guc_submission(fd));

This is not always true.

And it removes the clarity of being a simple wrapper.
-Chris
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