Mesa (staging/19.3): intel/perf: simplify the processing of OA reports
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Wed Dec 4 21:13:38 UTC 2019
Module: Mesa
Branch: staging/19.3
Commit: f7597aeefed4d500bf368f16066b7d7293ad0e9a
URL: http://cgit.freedesktop.org/mesa/mesa/commit/?id=f7597aeefed4d500bf368f16066b7d7293ad0e9a
Author: Lionel Landwerlin <lionel.g.landwerlin at intel.com>
Date: Tue Dec 3 16:33:25 2019 +0200
intel/perf: simplify the processing of OA reports
This is a more accurate description of what happens in processing the
OA reports.
Previously we only had a somewhat difficult to parse state machine
tracking the context ID.
What we really only need to do to decide if the delta between 2
reports (r0 & r1) should be accumulated in the query result is :
* whether the r0 is tagged with the context ID relevant to us
* if r0 is not tagged with our context ID and r1 is: does r0 have a
invalid context id? If not then we're in a case where i915 has
resubmitted the same context for execution through the execlist
submission port
v2: Update comment (Ken)
Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin at intel.com>
Cc: <mesa-stable at lists.freedesktop.org>
Reviewed-by: Kenneth Graunke <kenneth at whitecape.org>
(cherry picked from commit 8c0b05826304370ef9e5f1e607d0f0305a0eb759)
---
src/intel/perf/gen_perf.c | 64 ++++++++++++++++++++++++++---------------------
1 file changed, 36 insertions(+), 28 deletions(-)
diff --git a/src/intel/perf/gen_perf.c b/src/intel/perf/gen_perf.c
index 2df25487aad..20d84437e43 100644
--- a/src/intel/perf/gen_perf.c
+++ b/src/intel/perf/gen_perf.c
@@ -2216,6 +2216,17 @@ discard_all_queries(struct gen_perf_context *perf_ctx)
}
}
+/* Looks for the validity bit of context ID (dword 2) of an OA report. */
+static bool
+oa_report_ctx_id_valid(const struct gen_device_info *devinfo,
+ const uint32_t *report)
+{
+ assert(devinfo->gen >= 8);
+ if (devinfo->gen == 8)
+ return (report[0] & (1 << 25)) != 0;
+ return (report[0] & (1 << 16)) != 0;
+}
+
/**
* Accumulate raw OA counter values based on deltas between pairs of
* OA reports.
@@ -2243,7 +2254,7 @@ accumulate_oa_reports(struct gen_perf_context *perf_ctx,
uint32_t *last;
uint32_t *end;
struct exec_node *first_samples_node;
- bool in_ctx = true;
+ bool last_report_ctx_match = true;
int out_duration = 0;
assert(query->oa.map != NULL);
@@ -2289,6 +2300,7 @@ accumulate_oa_reports(struct gen_perf_context *perf_ctx,
switch (header->type) {
case DRM_I915_PERF_RECORD_SAMPLE: {
uint32_t *report = (uint32_t *)(header + 1);
+ bool report_ctx_match = true;
bool add = true;
/* Ignore reports that come before the start marker.
@@ -2317,35 +2329,30 @@ accumulate_oa_reports(struct gen_perf_context *perf_ctx,
* of OA counters while any other context is acctive.
*/
if (devinfo->gen >= 8) {
- if (in_ctx && report[2] != query->oa.result.hw_id) {
- DBG("i915 perf: Switch AWAY (observed by ID change)\n");
- in_ctx = false;
+ /* Consider that the current report matches our context only if
+ * the report says the report ID is valid.
+ */
+ report_ctx_match = oa_report_ctx_id_valid(devinfo, report) &&
+ report[2] == start[2];
+ if (report_ctx_match)
out_duration = 0;
- } else if (in_ctx == false && report[2] == query->oa.result.hw_id) {
- DBG("i915 perf: Switch TO\n");
- in_ctx = true;
-
- /* From experimentation in IGT, we found that the OA unit
- * might label some report as "idle" (using an invalid
- * context ID), right after a report for a given context.
- * Deltas generated by those reports actually belong to the
- * previous context, even though they're not labelled as
- * such.
- *
- * We didn't *really* Switch AWAY in the case that we e.g.
- * saw a single periodic report while idle...
- */
- if (out_duration >= 1)
- add = false;
- } else if (in_ctx) {
- assert(report[2] == query->oa.result.hw_id);
- DBG("i915 perf: Continuation IN\n");
- } else {
- assert(report[2] != query->oa.result.hw_id);
- DBG("i915 perf: Continuation OUT\n");
- add = false;
+ else
out_duration++;
- }
+
+ /* Only add the delta between <last, report> if the last report
+ * was clearly identified as our context, or if we have at most
+ * 1 report without a matching ID.
+ *
+ * The OA unit will sometimes label reports with an invalid
+ * context ID when i915 rewrites the execlist submit register
+ * with the same context as the one currently running. This
+ * happens when i915 wants to notify the HW of ringbuffer tail
+ * register update. We have to consider this report as part of
+ * our context as the 3d pipeline behind the OACS unit is still
+ * processing the operations started at the previous execlist
+ * submission.
+ */
+ add = last_report_ctx_match && out_duration < 2;
}
if (add) {
@@ -2355,6 +2362,7 @@ accumulate_oa_reports(struct gen_perf_context *perf_ctx,
}
last = report;
+ last_report_ctx_match = report_ctx_match;
break;
}
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