lkml.org 
[lkml]   [2015]   [Dec]   [14]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[tip:perf/core] perf top: Access hists->lock only if needed
Commit-ID:  151ee834cc946fa159ee406c62b4d5ce1ebd7115
Gitweb: http://git.kernel.org/tip/151ee834cc946fa159ee406c62b4d5ce1ebd7115
Author: Namhyung Kim <namhyung@kernel.org>
AuthorDate: Fri, 11 Dec 2015 11:56:54 +0900
Committer: Arnaldo Carvalho de Melo <acme@redhat.com>
CommitDate: Fri, 11 Dec 2015 08:34:49 -0300

perf top: Access hists->lock only if needed

The perf_top__record_precise_ip() releases and regrabs the
he->hists->lock because it can sleep if there's an error. But it should
be done conditionally as it slows down the fast path.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1449802616-16170-2-git-send-email-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
tools/perf/builtin-top.c | 28 +++++++++++++++-------------
1 file changed, 15 insertions(+), 13 deletions(-)

diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c
index 3b0978e..586798a 100644
--- a/tools/perf/builtin-top.c
+++ b/tools/perf/builtin-top.c
@@ -194,21 +194,23 @@ static void perf_top__record_precise_ip(struct perf_top *top,

pthread_mutex_unlock(&notes->lock);

- /*
- * This function is now called with he->hists->lock held.
- * Release it before going to sleep.
- */
- pthread_mutex_unlock(&he->hists->lock);
+ if (unlikely(err)) {
+ /*
+ * This function is now called with he->hists->lock held.
+ * Release it before going to sleep.
+ */
+ pthread_mutex_unlock(&he->hists->lock);
+
+ if (err == -ERANGE && !he->ms.map->erange_warned)
+ ui__warn_map_erange(he->ms.map, sym, ip);
+ else if (err == -ENOMEM) {
+ pr_err("Not enough memory for annotating '%s' symbol!\n",
+ sym->name);
+ sleep(1);
+ }

- if (err == -ERANGE && !he->ms.map->erange_warned)
- ui__warn_map_erange(he->ms.map, sym, ip);
- else if (err == -ENOMEM) {
- pr_err("Not enough memory for annotating '%s' symbol!\n",
- sym->name);
- sleep(1);
+ pthread_mutex_lock(&he->hists->lock);
}
-
- pthread_mutex_lock(&he->hists->lock);
}

static void perf_top__show_details(struct perf_top *top)

\
 
 \ /
  Last update: 2015-12-14 10:21    [W:0.701 / U:0.572 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site