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From: Jiri Olsa <jolsa@redhat.com>
To: Alexey Budankov <alexey.budankov@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>,
	Namhyung Kim <namhyung@kernel.org>,
	Alexander Shishkin <alexander.shishkin@linux.intel.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@redhat.com>, Andi Kleen <ak@linux.intel.com>,
	linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v3 8/9] perf record: implement control commands handling
Date: Wed, 20 May 2020 14:38:33 +0200	[thread overview]
Message-ID: <20200520123833.GG157452@krava> (raw)
In-Reply-To: <25f98682-5ef2-4257-f302-93b29da707a9@linux.intel.com>

On Wed, May 13, 2020 at 11:04:25AM +0300, Alexey Budankov wrote:
> 
> Implement handling of 'enable' and 'disable' control commands
> coming from control file descriptor.
> 
> Signed-off-by: Alexey Budankov <alexey.budankov@linux.intel.com>
> ---
>  tools/perf/builtin-record.c | 18 +++++++++++++++++-
>  1 file changed, 17 insertions(+), 1 deletion(-)
> 
> diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
> index 50dc2fe626e5..72f388623364 100644
> --- a/tools/perf/builtin-record.c
> +++ b/tools/perf/builtin-record.c
> @@ -1505,6 +1505,7 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
>  	bool disabled = false, draining = false;
>  	int fd;
>  	float ratio = 0;
> +	enum evlist_ctl_cmd cmd = EVLIST_CTL_CMD_UNSUPPORTED;
>  
>  	atexit(record__sig_exit);
>  	signal(SIGCHLD, sig_handler);
> @@ -1802,8 +1803,23 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
>  			 * Propagate error, only if there's any. Ignore positive
>  			 * number of returned events and interrupt error.
>  			 */
> -			if (err > 0 || (err < 0 && errno == EINTR))
> +			if (err > 0 || (err < 0 && errno == EINTR)) {
>  				err = 0;
> +				if (evlist__ctlfd_process(rec->evlist, &cmd) > 0) {
> +					switch (cmd) {
> +					case EVLIST_CTL_CMD_ENABLE:
> +						pr_info(EVLIST_ENABLED_MSG);
> +						break;
> +					case EVLIST_CTL_CMD_DISABLE:
> +						pr_info(EVLIST_DISABLED_MSG);
> +						break;
> +					case EVLIST_CTL_CMD_ACK:
> +					case EVLIST_CTL_CMD_UNSUPPORTED:
> +					default:
> +						break;
> +					}
> +				}
> +			}

so this will be processed only when:

	if (hits == rec->samples) {

what if there's always somethign in the buffer? will this stall?

>  			waking++;
>  
>  			if (evlist__filter_pollfd(rec->evlist, POLLERR | POLLHUP) == 0)

evlist__filter_pollfd will trigger draining if all the maps are closed,
but there's one more fd in pollfd now, will this prevent draining?

I wonder this would fit better to the sideband thread (util/sideband_evlist.c)
so we don't disturb the main thread with another check

jirka

> -- 
> 2.24.1
> 
> 


  reply	other threads:[~2020-05-20 12:38 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-13  7:53 [PATCH v3 0/9] perf: support enable and disable commands in stat and record modes Alexey Budankov
2020-05-13  7:59 ` [PATCH v3 1/9] perf evlist: introduce control file descriptors Alexey Budankov
2020-05-20 12:38   ` Jiri Olsa
2020-05-20 14:46     ` Alexey Budankov
2020-05-13  8:00 ` [PATCH v3 2/9] perf evlist: implement control command handling functions Alexey Budankov
2020-05-20 12:38   ` Jiri Olsa
2020-05-20 14:56     ` Alexey Budankov
2020-05-13  8:00 ` [PATCH v3 3/9] perf stat: factor out event handling loop into a function Alexey Budankov
2020-05-20 12:38   ` Jiri Olsa
2020-05-20 15:17     ` Alexey Budankov
2020-05-21 11:48       ` Jiri Olsa
2020-05-13  8:01 ` [PATCH v3 4/9] perf stat: extend -D,--delay option with -1 value Alexey Budankov
2020-05-13  8:02 ` [PATCH v3 5/9] perf stat: implement control commands handling Alexey Budankov
2020-05-13  8:03 ` [PATCH v3 6/9] perf stat: introduce --ctl-fd[-ack] options Alexey Budankov
2020-05-20 12:38   ` Jiri Olsa
2020-05-20 15:05     ` Alexey Budankov
2020-05-13  8:03 ` [PATCH v3 7/9] perf record: extend -D,--delay option with -1 value Alexey Budankov
2020-05-13  8:04 ` [PATCH v3 8/9] perf record: implement control commands handling Alexey Budankov
2020-05-20 12:38   ` Jiri Olsa [this message]
2020-05-20 18:06     ` Alexey Budankov
2020-05-13  8:05 ` [PATCH v3 9/9] perf record: introduce --ctl-fd[-ack] options Alexey Budankov
2020-05-20 12:38   ` Jiri Olsa
2020-05-20 15:21     ` Alexey Budankov
2020-05-18  8:08 ` [PATCH v3 0/9] perf: support enable and disable commands in stat and record modes Alexey Budankov
2020-05-20 10:55   ` Jiri Olsa
  -- strict thread matches above, loose matches on Subject: below --
2020-05-08 10:43 Alexey Budankov
2020-05-08 10:53 ` [PATCH v3 8/9] perf record: implement control commands handling Alexey Budankov

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