perf kvm: Only process events for vcpus of interest

Minimizing processing overhead for each sample - which becomes important
for the upcoming live mode when it has to deal with 100+k events per
second.

Signed-off-by: David Ahern <dsahern@gmail.com>
Cc: Dong Hao <haodong@linux.vnet.ibm.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/r/1349716656-48165-12-git-send-email-dsahern@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 16 insertions, 2 deletions

diff --git a/tools/perf/builtin-kvm.c b/tools/perf/builtin-kvm.c
index 260abc535b5..b98095edf1f 100644
--- a/tools/perf/builtin-kvm.c
+++ b/tools/perf/builtin-kvm.c
@@ -416,7 +416,10 @@ static double kvm_event_rel_stddev(int vcpu_id, struct kvm_event *event)
 static bool update_kvm_event(struct kvm_event *event, int vcpu_id,
                              u64 time_diff)
 {
-        kvm_update_event_stats(&event->total, time_diff);
+        if (vcpu_id == -1) {
+                kvm_update_event_stats(&event->total, time_diff);
+                return true;
+        }
 
         if (!kvm_event_expand(event, vcpu_id))
                 return false;
@@ -432,6 +435,12 @@ static bool handle_end_event(struct perf_kvm *kvm,
 {
         struct kvm_event *event;
         u64 time_begin, time_diff;
+        int vcpu;
+
+        if (kvm->trace_vcpu == -1)
+                vcpu = -1;
+        else
+                vcpu = vcpu_record->vcpu_id;
 
         event = vcpu_record->last_event;
         time_begin = vcpu_record->start_time;
@@ -461,7 +470,7 @@ static bool handle_end_event(struct perf_kvm *kvm,
         BUG_ON(timestamp < time_begin);
 
         time_diff = timestamp - time_begin;
-        return update_kvm_event(event, vcpu_record->vcpu_id, time_diff);
+        return update_kvm_event(event, vcpu, time_diff);
 }
 
 static
@@ -498,6 +507,11 @@ static bool handle_kvm_event(struct perf_kvm *kvm,
         if (!vcpu_record)
                 return true;
 
+        /* only process events for vcpus user cares about */
+        if ((kvm->trace_vcpu != -1) &&
+            (kvm->trace_vcpu != vcpu_record->vcpu_id))
+                return true;
+
         if (kvm->events_ops->is_begin_event(evsel, sample, &key))
                 return handle_begin_event(kvm, vcpu_record, &key, sample->time);