Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1404603 > unrolled thread

[PATCH v2 03/13] perf tools: Add API to pause a evlist

Back to article view | Back to linux.kernel

This discussion starts older than the indexed window; earlier articles aren't shown. The article labeled Started by below is the oldest one visible, not the original post.

Contents

  [PATCH v2 03/13] perf tools: Add API to pause a evlist Wang Nan <wangnan0@huawei.com> - 2016-05-20 18:50 +0200
    Re: [PATCH v2 03/13] perf tools: Add API to pause a evlist Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-05-20 20:10 +0200

#1404603 — [PATCH v2 03/13] perf tools: Add API to pause a evlist

perf_evlist__toggle_paused() is introduced to pause/resume events
in an evlist. Utilize PERF_EVENT_IOC_PAUSE_OUTPUT ioctl. Following
commits use perf_evlist__toggle_paused() to ensure overwrite
ring buffer is paused before reading.

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Signed-off-by: He Kuang <hekuang@huawei.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
---
 tools/perf/util/evlist.c | 22 ++++++++++++++++++++++
 tools/perf/util/evlist.h |  1 +
 2 files changed, 23 insertions(+)

diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
index 1a370db..f4bb8be 100644
--- a/tools/perf/util/evlist.c
+++ b/tools/perf/util/evlist.c
@@ -679,6 +679,28 @@ static struct perf_evsel *perf_evlist__event2evsel(struct perf_evlist *evlist,
 	return NULL;
 }
 
+int perf_evlist__toggle_paused(struct perf_evlist *evlist, bool pause)
+{
+	int i;
+
+	for (i = 0; i < evlist->nr_mmaps; i++) {
+		int fd = evlist->mmap[i].fd;
+		int err;
+
+		if (fd < 0)
+			continue;
+		err = ioctl(fd, PERF_EVENT_IOC_PAUSE_OUTPUT,
+			    pause ? 1 : 0);
+		if (err) {
+			err = (errno == 0 ? -EINVAL : -errno);
+			pr_err("Unable to pause output on %d: %s\n",
+			       fd, strerror(-err));
+			return err;
+		}
+	}
+	return 0;
+}
+
 /* When check_messup is true, 'end' must points to a good entry */
 static union perf_event *
 perf_mmap__read(struct perf_mmap *md, bool check_messup, u64 start,
diff --git a/tools/perf/util/evlist.h b/tools/perf/util/evlist.h
index 0d165b1..13234dc 100644
--- a/tools/perf/util/evlist.h
+++ b/tools/perf/util/evlist.h
@@ -136,6 +136,7 @@ void perf_evlist__mmap_read_catchup(struct perf_evlist *evlist, int idx);
 
 void perf_evlist__mmap_consume(struct perf_evlist *evlist, int idx);
 
+int perf_evlist__toggle_paused(struct perf_evlist *evlist, bool pause);
 int perf_evlist__open(struct perf_evlist *evlist);
 void perf_evlist__close(struct perf_evlist *evlist);
 
-- 
1.8.3.4

[toc] | [next] | [standalone]

#1404670

Em Fri, May 20, 2016 at 04:38:25PM +0000, Wang Nan escreveu:
> perf_evlist__toggle_paused() is introduced to pause/resume events
> in an evlist. Utilize PERF_EVENT_IOC_PAUSE_OUTPUT ioctl. Following
> commits use perf_evlist__toggle_paused() to ensure overwrite
> ring buffer is paused before reading.
> +{

int perf_evlist__toggle_paused(struct perf_evlist *evlist, bool pause)

Humm, toggle means, 1 -> 0 or 0 -> 1, not set(n), i.e. you either call
this:

int perf_evlist__toggle_paused(struct perf_evlist *evlist)

and keep an evsel->paused that starts with false and then you, in this
function, use:

	err = ioctl(fd, PERF_EVENT_IOC_PAUSE_OUTPUT, evsel->pause ? 1 : 0);
	if (!err)
		evsel->paused = !evsel->paused;
      

Or:

int perf_evlist__set_paused(struct perf_evlist *evlist, bool pause)

and do as you did below.

And you could do, to make it shorter, more intuitive:

	static inline int perf_evlist__pause(struct perf_evlist *evlist)
	{
		return perf_evlist__set_paused(evlist, true);
	}

	static inline int perf_evlist__continue(struct perf_evlist *evlist)
	{
		return perf_evlist__set_paused(evlist, false);
	}

I applied the first two patches.

- Arnaldo
 
> Signed-off-by: Wang Nan <wangnan0@huawei.com>
> Signed-off-by: He Kuang <hekuang@huawei.com>
> Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
> Cc: Jiri Olsa <jolsa@kernel.org>
> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
> Cc: Namhyung Kim <namhyung@kernel.org>
> Cc: Zefan Li <lizefan@huawei.com>
> Cc: pi3orama@163.com
> ---
>  tools/perf/util/evlist.c | 22 ++++++++++++++++++++++
>  tools/perf/util/evlist.h |  1 +
>  2 files changed, 23 insertions(+)
> 
> diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
> index 1a370db..f4bb8be 100644
> --- a/tools/perf/util/evlist.c
> +++ b/tools/perf/util/evlist.c
> @@ -679,6 +679,28 @@ static struct perf_evsel *perf_evlist__event2evsel(struct perf_evlist *evlist,
>  	return NULL;
>  }
>  
> +int perf_evlist__toggle_paused(struct perf_evlist *evlist, bool pause)
> +{
> +	int i;
> +
> +	for (i = 0; i < evlist->nr_mmaps; i++) {
> +		int fd = evlist->mmap[i].fd;
> +		int err;
> +
> +		if (fd < 0)
> +			continue;
> +		err = ioctl(fd, PERF_EVENT_IOC_PAUSE_OUTPUT,
> +			    pause ? 1 : 0);
> +		if (err) {
> +			err = (errno == 0 ? -EINVAL : -errno);
> +			pr_err("Unable to pause output on %d: %s\n",
> +			       fd, strerror(-err));
> +			return err;
> +		}
> +	}
> +	return 0;
> +}
> +
>  /* When check_messup is true, 'end' must points to a good entry */
>  static union perf_event *
>  perf_mmap__read(struct perf_mmap *md, bool check_messup, u64 start,
> diff --git a/tools/perf/util/evlist.h b/tools/perf/util/evlist.h
> index 0d165b1..13234dc 100644
> --- a/tools/perf/util/evlist.h
> +++ b/tools/perf/util/evlist.h
> @@ -136,6 +136,7 @@ void perf_evlist__mmap_read_catchup(struct perf_evlist *evlist, int idx);
>  
>  void perf_evlist__mmap_consume(struct perf_evlist *evlist, int idx);
>  
> +int perf_evlist__toggle_paused(struct perf_evlist *evlist, bool pause);
>  int perf_evlist__open(struct perf_evlist *evlist);
>  void perf_evlist__close(struct perf_evlist *evlist);
>  
> -- 
> 1.8.3.4

[toc] | [prev] | [standalone]

Back to top | Article view | linux.kernel

csiph-web