Messages in this thread Patch in this message | | | From | David Ahern <> | Subject | [PATCH 10/11] perf kvm: option to print events that exceed a threshold | Date | Thu, 11 Jul 2013 10:26:41 -0600 |
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This is useful to spot high latency blips.
Signed-off-by: David Ahern <dsahern@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Cc: Ingo Molnar <mingo@kernel.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com> Cc: Runzhen Wang <runzhen@linux.vnet.ibm.com> --- tools/perf/builtin-kvm.c | 24 ++++++++++++++++++++---- 1 file changed, 20 insertions(+), 4 deletions(-)
diff --git a/tools/perf/builtin-kvm.c b/tools/perf/builtin-kvm.c index 9336737..c2fede6 100644 --- a/tools/perf/builtin-kvm.c +++ b/tools/perf/builtin-kvm.c @@ -106,6 +106,7 @@ struct perf_kvm_stat { u64 total_time; u64 total_count; u64 lost_events; + u64 threshold; struct rb_root result; @@ -470,7 +471,7 @@ static bool update_kvm_event(struct kvm_event *event, int vcpu_id, 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; @@ -507,12 +508,24 @@ static bool handle_end_event(struct perf_kvm_stat *kvm, 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->threshold && time_diff > kvm->threshold) { + 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); } @@ -559,7 +572,7 @@ static bool handle_kvm_event(struct perf_kvm_stat *kvm, 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; } @@ -1333,6 +1346,8 @@ static int kvm_events_live(struct perf_kvm_stat *kvm, OPT_STRING('k', "key", &kvm->sort_key, "sort-key", "key for sorting: sample(sort by samples number)" " time (sort by avg time)"), + OPT_U64('T', "threshold", &kvm->threshold, + "show events that take longer than threshold usecs"), OPT_END() }; const char * const live_usage[] = { @@ -1363,6 +1378,7 @@ static int kvm_events_live(struct perf_kvm_stat *kvm, use_browser = 0; setup_browser(false); + kvm->threshold *= 1000; /* convert usec to nsec */ if (argc) { argc = parse_options(argc, argv, live_options, -- 1.7.10.1
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