perf kvm: Option to print events that exceed a duration
This is useful to spot high latency blips. It is normal for HLT reasons
to have long exit times, so strip those from the duration check.
v2: changed threshold to duration per acme's request
Signed-off-by: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Runzhen Wang <runzhen@linux.vnet.ibm.com>
Cc: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/r/1375926999-75129-1-git-send-email-dsahern@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/tools/perf/builtin-kvm.c b/tools/perf/builtin-kvm.c
index 2ceec81..fa2f3d7 100644
--- a/tools/perf/builtin-kvm.c
+++ b/tools/perf/builtin-kvm.c
@@ -106,6 +106,7 @@
u64 total_time;
u64 total_count;
u64 lost_events;
+ u64 duration;
const char *pid_str;
struct intlist *pid_list;
@@ -473,7 +474,7 @@
static bool handle_end_event(struct perf_kvm_stat *kvm,
struct vcpu_event_record *vcpu_record,
struct event_key *key,
- u64 timestamp)
+ struct perf_sample *sample)
{
struct kvm_event *event;
u64 time_begin, time_diff;
@@ -510,12 +511,24 @@
vcpu_record->start_time = 0;
/* seems to happen once in a while during live mode */
- if (timestamp < time_begin) {
+ if (sample->time < time_begin) {
pr_debug("End time before begin time; skipping event.\n");
return true;
}
- time_diff = timestamp - time_begin;
+ time_diff = sample->time - time_begin;
+
+ if (kvm->duration && time_diff > kvm->duration) {
+ char decode[32];
+
+ kvm->events_ops->decode_key(kvm, &event->key, decode);
+ if (strcmp(decode, "HLT")) {
+ pr_info("%" PRIu64 " VM %d, vcpu %d: %s event took %" PRIu64 "usec\n",
+ sample->time, sample->pid, vcpu_record->vcpu_id,
+ decode, time_diff/1000);
+ }
+ }
+
return update_kvm_event(event, vcpu, time_diff);
}
@@ -562,7 +575,7 @@
return handle_begin_event(kvm, vcpu_record, &key, sample->time);
if (kvm->events_ops->is_end_event(evsel, sample, &key))
- return handle_end_event(kvm, vcpu_record, &key, sample->time);
+ return handle_end_event(kvm, vcpu_record, &key, sample);
return true;
}
@@ -1429,6 +1442,8 @@
OPT_STRING('k', "key", &kvm->sort_key, "sort-key",
"key for sorting: sample(sort by samples number)"
" time (sort by avg time)"),
+ OPT_U64(0, "duration", &kvm->duration,
+ "show events other than HALT that take longer than duration usecs"),
OPT_END()
};
const char * const live_usage[] = {
@@ -1467,6 +1482,8 @@
usage_with_options(live_usage, live_options);
}
+ kvm->duration *= NSEC_PER_USEC; /* convert usec to nsec */
+
/*
* target related setups
*/