On 24/07/17 16:55, Chris Wilson wrote:
Quoting Lionel Landwerlin (2017-06-22 02:25:28)
Counter related to timings will be sensitive to any delay introduced
by the software. In particular if our begin & end of performance
queries end up in different batches, time related counters will
exhibit biffer values caused by the time it takes for the kernel
driver to load new requests into the hardware.
Signed-off-by: Lionel Landwerlin <lionel.g.landwer...@intel.com>
---
src/mesa/drivers/dri/i965/brw_performance_query.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/src/mesa/drivers/dri/i965/brw_performance_query.c
b/src/mesa/drivers/dri/i965/brw_performance_query.c
index 06576a54d03..6b874d0bbee 100644
--- a/src/mesa/drivers/dri/i965/brw_performance_query.c
+++ b/src/mesa/drivers/dri/i965/brw_performance_query.c
@@ -1063,6 +1063,14 @@ brw_end_perf_query(struct gl_context *ctx,
obj->oa.begin_report_id + 1);
}
+ /* We flush the batchbuffer here to minimize the chances that MI_RPC
+ * delimiting commands end up in different batchbuffers. If that's the
+ * case, the measurement will include the time it takes for the kernel
+ * scheduler to load a new request into the hardware. This is manifested
+ * in tools like frameretrace by spikes in the "GPU Core Clocks"
+ * counter.
+ */
+ intel_batchbuffer_flush(brw);
Doesn't this make more sense before the start of the perf-query, because
you want the bookkends in the same batch? Flushing afterwards does
nothing to improve the likelihood of this query being contained.
Indeed having it after might produce a spike in the first query.
Will send a follow up fix (and verify spikes are still gone).
Tough we'll still need this commit in stable before the following.
Thanks!
--brw->perfquery.n_active_oa_queries;
/* NB: even though the query has now ended, it can't be accumulated
--
2.11.0
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