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perf stat: Use affinity for closing file descriptors

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Closing a perf fd can also trigger an IPI to the target CPU.

Use the same affinity technique as we use for reading/enabling events to
closing to optimize the CPU transitions.

Before on a large test case with 94 CPUs:

  % time     seconds  usecs/call     calls    errors syscall
  ------ ----------- ----------- --------- --------- ----------------
   32.56    3.085463          50     61483           close

  After:

   10.54    0.735704          11     61485           close

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Link: http://lore.kernel.org/lkml/20191121001522.180827-8-andi@firstfloor.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Andi Kleen 2019-11-20 16:15:17 -08:00 committed by Arnaldo Carvalho de Melo
parent 99d6141d67
commit 7736627b86
1 changed files with 29 additions and 2 deletions
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31
tools/perf/util/evlist.c
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@ -18,6 +18,7 @@
#include "debug.h"
#include "units.h"
#include <internal/lib.h> // page_size
#include "affinity.h"
#include "../perf.h"
#include "asm/bug.h"
#include "bpf-event.h"
@ -1169,9 +1170,35 @@ void perf_evlist__set_selected(struct evlist *evlist,
void evlist__close(struct evlist *evlist)
{
struct evsel *evsel;
struct affinity affinity;
int cpu, i;
evlist__for_each_entry_reverse(evlist, evsel)
evsel__close(evsel);
/*
* With perf record core.cpus is usually NULL.
* Use the old method to handle this for now.
*/
if (!evlist->core.cpus) {
evlist__for_each_entry_reverse(evlist, evsel)
evsel__close(evsel);
return;
}
if (affinity__setup(&affinity) < 0)
return;
evlist__for_each_cpu(evlist, i, cpu) {
affinity__set(&affinity, cpu);
evlist__for_each_entry_reverse(evlist, evsel) {
if (evsel__cpu_iter_skip(evsel, cpu))
continue;
perf_evsel__close_cpu(&evsel->core, evsel->cpu_iter - 1);
}
}
affinity__cleanup(&affinity);
evlist__for_each_entry_reverse(evlist, evsel) {
perf_evsel__free_fd(&evsel->core);
perf_evsel__free_id(&evsel->core);
}
}
static int perf_evlist__create_syswide_maps(struct evlist *evlist)