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* [Intel-gfx] [PATCH] drm/i915/perf: Clear out entire reports after reading if not power of 2 size
@ 2023-05-22 20:17 Ashutosh Dixit
  2023-05-22 21:19 ` [Intel-gfx] ✗ Fi.CI.BAT: failure for " Patchwork
                   ` (4 more replies)
  0 siblings, 5 replies; 9+ messages in thread
From: Ashutosh Dixit @ 2023-05-22 20:17 UTC (permalink / raw)
  To: intel-gfx; +Cc: dri-devel

Clearing out report id and timestamp as means to detect unlanded reports
only works if report size is power of 2. That is, only when report size is
a sub-multiple of the OA buffer size can we be certain that reports will
land at the same place each time in the OA buffer (after rewind). If report
size is not a power of 2, we need to zero out the entire report to be able
to detect unlanded reports reliably.

Cc: Umesh Nerlige Ramappa <umesh.nerlige.ramappa@intel.com>
Signed-off-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
---
 drivers/gpu/drm/i915/i915_perf.c | 17 +++++++++++------
 1 file changed, 11 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_perf.c b/drivers/gpu/drm/i915/i915_perf.c
index 19d5652300eeb..58284156428dc 100644
--- a/drivers/gpu/drm/i915/i915_perf.c
+++ b/drivers/gpu/drm/i915/i915_perf.c
@@ -877,12 +877,17 @@ static int gen8_append_oa_reports(struct i915_perf_stream *stream,
 			stream->oa_buffer.last_ctx_id = ctx_id;
 		}
 
-		/*
-		 * Clear out the report id and timestamp as a means to detect unlanded
-		 * reports.
-		 */
-		oa_report_id_clear(stream, report32);
-		oa_timestamp_clear(stream, report32);
+		if (is_power_of_2(report_size)) {
+			/*
+			 * Clear out the report id and timestamp as a means
+			 * to detect unlanded reports.
+			 */
+			oa_report_id_clear(stream, report32);
+			oa_timestamp_clear(stream, report32);
+		} else {
+			/* Zero out the entire report */
+			memset(report32, 0, report_size);
+		}
 	}
 
 	if (start_offset != *offset) {
-- 
2.38.0


^ permalink raw reply related	[flat|nested] 9+ messages in thread
* [Intel-gfx] [PATCH] drm/i915/perf: Clear out entire reports after reading if not power of 2 size
@ 2023-05-23 20:40 Ashutosh Dixit
  0 siblings, 0 replies; 9+ messages in thread
From: Ashutosh Dixit @ 2023-05-23 20:40 UTC (permalink / raw)
  To: intel-gfx; +Cc: dri-devel

Clearing out report id and timestamp as means to detect unlanded reports
only works if report size is power of 2. That is, only when report size is
a sub-multiple of the OA buffer size can we be certain that reports will
land at the same place each time in the OA buffer (after rewind). If report
size is not a power of 2, we need to zero out the entire report to be able
to detect unlanded reports reliably.

v2: Add Fixes tag (Umesh)

Fixes: 1cc064dce4ed ("drm/i915/perf: Add support for OA media units")
Reviewed-by: Umesh Nerlige Ramappa <umesh.nerlige.ramappa@intel.com>
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Signed-off-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
---
 drivers/gpu/drm/i915/i915_perf.c | 17 +++++++++++------
 1 file changed, 11 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_perf.c b/drivers/gpu/drm/i915/i915_perf.c
index 19d5652300eeb..58284156428dc 100644
--- a/drivers/gpu/drm/i915/i915_perf.c
+++ b/drivers/gpu/drm/i915/i915_perf.c
@@ -877,12 +877,17 @@ static int gen8_append_oa_reports(struct i915_perf_stream *stream,
 			stream->oa_buffer.last_ctx_id = ctx_id;
 		}
 
-		/*
-		 * Clear out the report id and timestamp as a means to detect unlanded
-		 * reports.
-		 */
-		oa_report_id_clear(stream, report32);
-		oa_timestamp_clear(stream, report32);
+		if (is_power_of_2(report_size)) {
+			/*
+			 * Clear out the report id and timestamp as a means
+			 * to detect unlanded reports.
+			 */
+			oa_report_id_clear(stream, report32);
+			oa_timestamp_clear(stream, report32);
+		} else {
+			/* Zero out the entire report */
+			memset(report32, 0, report_size);
+		}
 	}
 
 	if (start_offset != *offset) {
-- 
2.38.0


^ permalink raw reply related	[flat|nested] 9+ messages in thread
end of thread, other threads:[~2023-05-23 20:40 UTC | newest]

Thread overview: 9+ messages (download: mbox.gz follow: Atom feed
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2023-05-22 20:17 [Intel-gfx] [PATCH] drm/i915/perf: Clear out entire reports after reading if not power of 2 size Ashutosh Dixit
2023-05-22 21:19 ` [Intel-gfx] ✗ Fi.CI.BAT: failure for " Patchwork
2023-05-22 21:34 ` [Intel-gfx] [PATCH] " Umesh Nerlige Ramappa
2023-05-22 21:50   ` Dixit, Ashutosh
2023-05-23 17:50     ` Umesh Nerlige Ramappa
2023-05-23  8:32 ` [Intel-gfx] ✓ Fi.CI.BAT: success for drm/i915/perf: Clear out entire reports after reading if not power of 2 size (rev2) Patchwork
2023-05-23 10:21 ` [Intel-gfx] ✓ Fi.CI.IGT: " Patchwork
2023-05-23 14:31 ` [Intel-gfx] [PATCH] drm/i915/perf: Clear out entire reports after reading if not power of 2 size Lionel Landwerlin
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2023-05-23 20:40 Ashutosh Dixit

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