From: David Ahern <dsahern@gmail.com>
To: Gleb Natapov <gleb@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
Ingo Molnar <mingo@kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Arnaldo Carvalho de Melo <acme@infradead.org>,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
Thomas Gleixner <tglx@linutronix.de>,
Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [GIT PULL] perf changes for v3.8
Date: Sat, 22 Dec 2012 12:30:35 -0700 [thread overview]
Message-ID: <50D60A5B.1020700@gmail.com> (raw)
In-Reply-To: <20121217102000.GE11016@redhat.com>
On 12/17/12 3:20 AM, Gleb Natapov wrote:
> Does the regression happen because of commit 20b279ddb38c. If it does I
> think it is safe to revert it. KVM disables PEBS during guest entry now, so
> VMs shouldn't be blowing up (they do not in my testing) and if they still
> do we can disable the counter that has PEBS enabled on a guest entry too.
> Yes, if user runs "perf record -e cycles:ppG" he will not know that
> kernel ignored :pp modifier (with 20b279ddb38c he will get an error), but
> at least old binaries will continue working and new binaries can do the
> checking in userspace.
>
Your patch alone was not enough. Start here:
https://lkml.org/lkml/2012/7/12/3
And from your response:
https://lkml.org/lkml/2012/7/12/337
"Do not run perf kvm. It does not set exclude_guest and :p and :pp is
not compatible with guest profiling and should be disallowed. Again
Peter's patch takes care of this."
20b279ddb38c is Peter's patch -- kernel side enforcement that
exclude_guest needs to be set when using precise mode.
David
next prev parent reply other threads:[~2012-12-22 19:30 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-12-11 9:09 Ingo Molnar
2012-12-13 2:53 ` Linus Torvalds
2012-12-13 3:02 ` David Ahern
2012-12-13 3:09 ` Linus Torvalds
2012-12-13 3:16 ` David Ahern
2012-12-13 3:25 ` David Ahern
2012-12-13 3:34 ` Linus Torvalds
2012-12-13 3:43 ` David Ahern
2012-12-13 3:51 ` Linus Torvalds
2012-12-13 4:31 ` David Ahern
2012-12-13 4:46 ` Linus Torvalds
2012-12-13 7:27 ` Ingo Molnar
2012-12-13 7:30 ` Ingo Molnar
2012-12-13 14:30 ` David Ahern
2012-12-13 14:38 ` David Ahern
2012-12-13 16:03 ` Linus Torvalds
2012-12-13 16:24 ` David Ahern
2012-12-13 16:33 ` Linus Torvalds
2012-12-13 16:59 ` Ingo Molnar
2012-12-13 17:10 ` Linus Torvalds
2012-12-13 17:31 ` Ingo Molnar
2012-12-17 4:43 ` David Ahern
2012-12-22 19:22 ` David Ahern
2012-12-23 0:00 ` Linus Torvalds
2012-12-13 17:02 ` Linus Torvalds
2012-12-13 17:30 ` David Ahern
2012-12-13 17:36 ` Ingo Molnar
2012-12-13 19:12 ` David Ahern
2012-12-13 7:48 ` [PATCH] Revert "perf: Require exclude_guest to use PEBS - kernel side enforcement" Ingo Molnar
[not found] ` <20121217102000.GE11016@redhat.com>
2012-12-22 19:30 ` David Ahern [this message]
2012-12-23 9:23 ` [GIT PULL] perf changes for v3.8 Gleb Natapov
2012-12-23 23:17 ` David Ahern
2012-12-24 10:36 ` Gleb Natapov
2012-12-13 17:04 ` [PATCH] x86: fix perf build with uclibc toolchains Florian Fainelli
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