lkml.org 
[lkml]   [2019]   [Dec]   [3]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 05/23] perf stat: Use affinity for closing file descriptors
Date
From: Andi Kleen <ak@linux.intel.com>

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>
---
tools/perf/util/evlist.c | 31 +++++++++++++++++++++++++++++--
1 file changed, 29 insertions(+), 2 deletions(-)

diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
index dae6e846b2f8..2e8d38a324be 100644
--- a/tools/perf/util/evlist.c
+++ b/tools/perf/util/evlist.c
@@ -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)
--
2.21.0
\
 
 \ /
  Last update: 2019-12-03 14:57    [W:0.090 / U:0.720 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site