From: Peter Zijlstra <peterz@infradead.org>
To: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>,
x86@kernel.org, Borislav Petkov <bp@alien8.de>,
Ingo Molnar <mingo@redhat.com>,
linux-kernel@vger.kernel.org, vince@deater.net,
eranian@google.com, Arnaldo Carvalho de Melo <acme@infradead.org>
Subject: Re: [PATCH 2/2] perf: Disable the event on a truncated AUX record
Date: Wed, 11 May 2016 11:13:33 +0200 [thread overview]
Message-ID: <20160511091333.GA3190@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <1462886313-13660-3-git-send-email-alexander.shishkin@linux.intel.com>
On Tue, May 10, 2016 at 04:18:33PM +0300, Alexander Shishkin wrote:
> When the PMU driver reports a truncated AUX record, it effectively means
> that there is no more usable room in the event's AUX buffer (even though
> there may still be some room, so that perf_aux_output_begin() doesn't take
> action). At this point the consumer still has to be woken up and the event
> has to be disabled, otherwise the event will just keep spinning between
> perf_aux_output_begin() and perf_aux_output_end() until its context gets
> unscheduled.
>
> Again, for cpu-wide events this means never, so once in this condition,
> they will be forever losing data.
>
> Fix this by disabling the event and waking up the consumer in case of a
> truncated AUX record.
> + if (wakeup) {
> + if (truncated)
> + handle->event->pending_disable = 1;
> + perf_output_wakeup(handle);
> + }
Does the userspace tool know how to deal with this and re-enable it?
next prev parent reply other threads:[~2016-05-11 9:13 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-10 13:18 [PATCH 0/2] perf, pt: Fix massive data losses Alexander Shishkin
2016-05-10 13:18 ` [PATCH 1/2] perf/x86/intel/pt: Generate PMI in the STOP region as well Alexander Shishkin
2016-05-12 10:34 ` [tip:perf/core] " tip-bot for Alexander Shishkin
2016-05-12 12:28 ` Alexander Shishkin
2016-05-12 12:47 ` Ingo Molnar
2016-05-12 13:03 ` Alexander Shishkin
2016-05-12 12:48 ` [tip:perf/urgent] " tip-bot for Alexander Shishkin
2016-05-17 7:31 ` Alexander Shishkin
2016-05-17 8:40 ` Ingo Molnar
2016-05-21 5:25 ` Greg KH
2016-05-10 13:18 ` [PATCH 2/2] perf: Disable the event on a truncated AUX record Alexander Shishkin
2016-05-11 9:13 ` Peter Zijlstra [this message]
2016-05-11 9:41 ` Alexander Shishkin
2016-05-11 9:49 ` Peter Zijlstra
2016-05-11 10:05 ` Alexander Shishkin
2016-05-12 10:35 ` [tip:perf/core] perf/core: " tip-bot for Alexander Shishkin
2016-05-12 12:49 ` [tip:perf/urgent] " tip-bot for Alexander Shishkin
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20160511091333.GA3190@twins.programming.kicks-ass.net \
--to=peterz@infradead.org \
--cc=acme@infradead.org \
--cc=alexander.shishkin@linux.intel.com \
--cc=bp@alien8.de \
--cc=eranian@google.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@redhat.com \
--cc=tglx@linutronix.de \
--cc=vince@deater.net \
--cc=x86@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox
Powered by JetHome