[PATCH v5 13/13] perf stat: Use affinity for enabling/disabling events

Andi Kleen
2019-11-07T18:17:11Z

From: Andi Kleen <ak@linux.intel.com>

Restructure event enabling/disabling to use affinity, which
minimizes the number of IPIs needed.

Before on a large test case with 94 CPUs:

% time seconds usecs/call calls errors syscall
------ ----------- ----------- --------- --------- ----------------
54.65 1.899986 22 84812 660 ioctl

after:

39.21 0.930451 10 84796 644 ioctl

Signed-off-by: Andi Kleen <ak@linux.intel.com>

---

v2: Use new iterator macros
v3: Use new iterator macros
v4: Update iterators again
---
tools/perf/util/evlist.c | 40 +++++++++++++++++++++++++++++++++++++---
1 file changed, 37 insertions(+), 3 deletions(-)

diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
index 33080f79b977..571bb102b432 100644
--- a/tools/perf/util/evlist.c
+++ b/tools/perf/util/evlist.c
@@ -378,11 +378,28 @@ bool evsel__cpu_iter_skip(struct evsel *ev, int cpu)
void evlist__disable(struct evlist *evlist)
{
struct evsel *pos;
+ struct affinity affinity;
+ int cpu, i;
+
+ if (affinity__setup(&affinity) < 0)
+ return;
+
+ evlist__for_each_cpu (evlist, i, cpu) {
+ affinity__set(&affinity, cpu);

+ evlist__for_each_entry(evlist, pos) {
+ if (evsel__cpu_iter_skip(pos, cpu))
+ continue;
+ if (pos->disabled || !perf_evsel__is_group_leader(pos) || !pos->core.fd)
+ continue;
+ evsel__disable_cpu(pos, pos->cpu_iter - 1);
+ }
+ }
+ affinity__cleanup(&affinity);
evlist__for_each_entry(evlist, pos) {
- if (pos->disabled || !perf_evsel__is_group_leader(pos) || !pos->core.fd)
+ if (!perf_evsel__is_group_leader(pos) || !pos->core.fd)
continue;
- evsel__disable(pos);
+ pos->disabled = true;
}

evlist->enabled = false;
@@ -391,11 +408,28 @@ void evlist__disable(struct evlist *evlist)
void evlist__enable(struct evlist *evlist)
{
struct evsel *pos;
+ struct affinity affinity;
+ int cpu, i;

+ if (affinity__setup(&affinity) < 0)
+ return;
+
+ evlist__for_each_cpu (evlist, i, cpu) {
+ affinity__set(&affinity, cpu);
+
+ evlist__for_each_entry(evlist, pos) {
+ if (evsel__cpu_iter_skip(pos, cpu))
+ continue;
+ if (!perf_evsel__is_group_leader(pos) || !pos->core.fd)
+ continue;
+ evsel__enable_cpu(pos, pos->cpu_iter - 1);
+ }
+ }
+ affinity__cleanup(&affinity);
evlist__for_each_entry(evlist, pos) {
if (!perf_evsel__is_group_leader(pos) || !pos->core.fd)
continue;
- evsel__enable(pos);
+ pos->disabled = false;
}

evlist->enabled = true;
--
2.23.0