From: Alexey Budankov <alexey.budankov@linux.intel.com>
To: Jiri Olsa <jolsa@redhat.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 21:06:49 +0300 [thread overview]
Message-ID: <df2cd76d-a9ae-7092-1ee2-83fee8f557c8@linux.intel.com> (raw)
In-Reply-To: <20200520123833.GG157452@krava>
On 20.05.2020 15:38, Jiri Olsa wrote:
> 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?
Good catch. This needs redesign to notice pending commands during
active trace streaming. The same is regarding 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
~Alexey
next prev parent reply other threads:[~2020-05-20 18:06 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
2020-05-20 18:06 ` Alexey Budankov [this message]
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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