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authorJiri Olsa <jolsa@kernel.org>2018-11-05 21:23:40 +0100
committerArnaldo Carvalho de Melo <acme@redhat.com>2018-12-17 14:58:03 -0300
commit94ad6e7e3606454498aeac1fdd1b9de5c1e6735a (patch)
tree00954eb7ea985e5053f7c1b53fc9c419a1316d4e /tools/perf/builtin-top.c
parent16c66bc167cc52992f66748aed7ac21396189457 (diff)
perf top: Use cond variable instead of a lock
Use conditional variable logic to synchronize between the reading and processing threads. Currently it's done by having mutex around rotation code. Using a POSIX cond variable to sync both threads after queues rotation: Process thread: - Detects data - Switches queues - Sets rotate variable - Waits in pthread_cond_wait() Read thread: - Detects rotate is set - Kicks the process thread with a pthread_cond_signal() After this rotation is safely completed and both threads can continue with the new queue. Signed-off-by: Jiri Olsa <jolsa@kernel.org> Acked-by: David S. Miller <davem@davemloft.net> Acked-by: Namhyung Kim <namhyung@kernel.org> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/n/tip-3rdeg23rv3brvy1pwt3igvyw@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools/perf/builtin-top.c')
-rw-r--r--tools/perf/builtin-top.c24
1 files changed, 17 insertions, 7 deletions
diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c
index 75afeae7f04d..aad58643102e 100644
--- a/tools/perf/builtin-top.c
+++ b/tools/perf/builtin-top.c
@@ -846,13 +846,18 @@ static void perf_top__mmap_read_idx(struct perf_top *top, int idx)
if (ret && ret != -1)
break;
- pthread_mutex_lock(&top->qe.lock);
ret = ordered_events__queue(top->qe.in, event, timestamp, 0);
- pthread_mutex_unlock(&top->qe.lock);
-
- perf_mmap__consume(md);
if (ret)
break;
+
+ perf_mmap__consume(md);
+
+ if (top->qe.rotate) {
+ pthread_mutex_lock(&top->qe.mutex);
+ top->qe.rotate = false;
+ pthread_cond_signal(&top->qe.cond);
+ pthread_mutex_unlock(&top->qe.mutex);
+ }
}
perf_mmap__read_done(md);
@@ -1059,9 +1064,12 @@ static void *process_thread(void *arg)
continue;
}
- pthread_mutex_lock(&top->qe.lock);
out = rotate_queues(top);
- pthread_mutex_unlock(&top->qe.lock);
+
+ pthread_mutex_lock(&top->qe.mutex);
+ top->qe.rotate = true;
+ pthread_cond_wait(&top->qe.cond, &top->qe.mutex);
+ pthread_mutex_unlock(&top->qe.mutex);
if (ordered_events__flush(out, OE_FLUSH__TOP))
pr_err("failed to process events\n");
@@ -1151,7 +1159,8 @@ static void init_process_thread(struct perf_top *top)
ordered_events__set_copy_on_queue(&top->qe.data[0], true);
ordered_events__set_copy_on_queue(&top->qe.data[1], true);
top->qe.in = &top->qe.data[0];
- pthread_mutex_init(&top->qe.lock, NULL);
+ pthread_mutex_init(&top->qe.mutex, NULL);
+ pthread_cond_init(&top->qe.cond, NULL);
}
static int __cmd_top(struct perf_top *top)
@@ -1271,6 +1280,7 @@ static int __cmd_top(struct perf_top *top)
out_join:
pthread_join(thread, NULL);
out_join_thread:
+ pthread_cond_signal(&top->qe.cond);
pthread_join(thread_process, NULL);
out_delete:
perf_session__delete(top->session);