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From: Ingo Molnar <mingo@kernel.org>
To: Borislav Petkov <bp@alien8.de>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Robert Richter <rric@kernel.org>, Vince Weaver <vince@deater.net>,
	lkml <linux-kernel@vger.kernel.org>
Subject: Re: [RFC PATCH] perf/stat: Add --disable-hwdt
Date: Mon, 6 Feb 2017 13:44:48 +0100	[thread overview]
Message-ID: <20170206124447.GA12772@gmail.com> (raw)
In-Reply-To: <20170206124116.7jmrmufthqtnd3dc@pd.tnic>


* Borislav Petkov <bp@alien8.de> wrote:

> On Mon, Feb 06, 2017 at 01:22:31PM +0100, Ingo Molnar wrote:
> > Looks sensible, and I'd in fact make this the new default behavior (if root runs 
> > perf stat) - i.e. add a flag to re-enable it, for the rare case where we want to 
> > debug a hard deadlock while running perf stat ...
> 
> I'd probably only need to save the previous state, in case it was
> disabled for whatever reason.
> 
> So actually, I'll make it so that we restore the previous state at exit.
> Whatever it was. But while perf stat runs as root, we will disable it by
> default.
> 
> /me scratches head a bit...
> 
> Oh ok, even better - no need for a cmdline option then.
> 
> Or does it *ever* make sense to have watchdog running *while* perf stat
> runs too?

Yeah, if for some whatever reason perf locks up while running perf stat as root, 
so I'd keep the option, as a general principle. :-/

Thanks,

	Ingo

  reply	other threads:[~2017-02-06 12:44 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-02-06 12:15 [RFC PATCH] perf/stat: Add --disable-hwdt Borislav Petkov
2017-02-06 12:22 ` Ingo Molnar
2017-02-06 12:41   ` Borislav Petkov
2017-02-06 12:44     ` Ingo Molnar [this message]
2017-02-06 12:49       ` Borislav Petkov
2017-02-06 13:18         ` Robert Richter
2017-02-06 13:23           ` Borislav Petkov
2017-02-07  7:25             ` Ingo Molnar
2017-02-07 10:54               ` Borislav Petkov
2017-02-07 15:06                 ` Borislav Petkov
2017-02-11 17:03                   ` Borislav Petkov
2017-02-11 17:59                     ` Ingo Molnar
2017-02-11 18:32                       ` Borislav Petkov
2017-02-11 20:41                         ` Ingo Molnar
2017-03-07  7:21                         ` [tip:perf/core] perf stat: Issue a HW watchdog disable hint tip-bot for Borislav Petkov
2017-02-06 14:23           ` [RFC PATCH] perf/stat: Add --disable-hwdt Vince Weaver
2017-02-06 17:02             ` Borislav Petkov
2017-02-07  1:08         ` Borislav Petkov
2017-02-07  1:09           ` [PATCH 1/2] tools/lib/api/fs: Add procfs int read/write helpers Borislav Petkov
2017-02-07  1:43             ` Arnaldo Carvalho de Melo
2017-02-07 10:30               ` Borislav Petkov
2017-02-07 15:00                 ` Arnaldo Carvalho de Melo
2017-02-07 15:08                   ` Borislav Petkov
2017-02-07 15:34                     ` Arnaldo Carvalho de Melo
2017-02-07  1:10           ` [PATCH 2/2] perf stat: Disable HW watchdog around a perf stat session Borislav Petkov
2017-02-07  1:45             ` Arnaldo Carvalho de Melo

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