From: Alexander Yarygin <yarygin@xxxxxxxxxxxxxxxxxx>
Every event in the perf-kvm has a 'stats' structure, which contains
max/min/average/etc times of handling this event.
The problem is that the 'perf-kvm stat report' command always shows
that 'min time' is 0us for every event. Example:
# perf kvm stat report
Analyze events for all VCPUs:
VM-EXIT Samples Samples% Time% Min Time Max Time
Avg time
[..]
0xB2 MSCH 12 0.07% 0.00% 0us 8us
7.31us ( +- 2.11% )
0xB2 CHSC 12 0.07% 0.00% 0us 18us
9.39us ( +- 9.49% )
0xB2 STPX 8 0.05% 0.00% 0us 2us
1.88us ( +- 7.18% )
0xB2 STSI 7 0.04% 0.00% 0us 44us
16.49us ( +- 38.20% )
[..]
This happens because 'stats' structure is not initialized and
stats->min equals to 0. Lets initialize the structure for every
event after it's allocation using init_stats() function. This initialize
stats->min to -1 and makes 'Min time' statistics counting work:
# perf kvm stat report
Analyze events for all VCPUs:
VM-EXIT Samples Samples% Time% Min Time Max Time
Avg time
[..]
0xB2 MSCH 12 0.07% 0.00% 6us 8us
7.31us ( +- 2.11% )
0xB2 CHSC 12 0.07% 0.00% 7us 18us
9.39us ( +- 9.49% )
0xB2 STPX 8 0.05% 0.00% 1us 2us
1.88us ( +- 7.18% )
0xB2 STSI 7 0.04% 0.00% 1us 44us
16.49us ( +- 38.20% )
[..]
Signed-off-by: Alexander Yarygin <yarygin@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Christian Borntraeger <borntraeger@xxxxxxxxxx>
---
tools/perf/builtin-kvm.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/tools/perf/builtin-kvm.c b/tools/perf/builtin-kvm.c
index 21c164b..0f1e5a2 100644
--- a/tools/perf/builtin-kvm.c
+++ b/tools/perf/builtin-kvm.c
@@ -404,6 +404,7 @@ static struct kvm_event *kvm_alloc_init_event(struct event_key *key)
}
event->key = *key;
+ init_stats(&event->total.stats);
return event;
}
--
1.7.9.5
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