From: Peter Zijlstra <peterz@infradead.org>
To: Stephane Eranian <eranian@google.com>
Cc: mingo@elte.hu, Linus Torvalds <torvalds@osdl.org>,
linux-kernel@vger.kernel.org
Subject: Re: [RFC,PATCH 2/2] perf, x86: Utilize the LBRs for machine/oops debugging
Date: Mon, 29 Mar 2010 16:13:44 +0200 [thread overview]
Message-ID: <1269872024.12097.337.camel@laptop> (raw)
In-Reply-To: <bd4cb8901003290547u1baa58fer762da04790a195ab@mail.gmail.com>
On Mon, 2010-03-29 at 13:47 +0100, Stephane Eranian wrote:
> On Mon, Mar 29, 2010 at 1:20 PM, Peter Zijlstra <a.p.zijlstra@chello.nl> wrote:
> > The LBRs are relatively cheap to keep enabled and provide some history
> > to OOPSen, also some CPUs are reported to keep them over soft-reset,
> > which allows us to use them to debug things like tripple faults.
> >
> > Therefore introduce a boot option: lbr_debug=on, which always enable
> > the LBRs and will print the LBRs on CPU init and die().
> >
>
> When this is enabled, it will prevent changing the LBR configuration to
> record only selected branches. Unless you are willing to accept filtered
> content in the kernel dump.
Sure, but since we don't support that silly config reg anyway that's
pretty much not an issue ;-)
next prev parent reply other threads:[~2010-03-29 14:13 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-03-29 12:20 [PATCH 0/2] perf: Use LBR for machine/oops debugging Peter Zijlstra
2010-03-29 12:20 ` [PATCH 1/2] perf, x86: fix __initconst vs const Peter Zijlstra
2010-03-29 12:20 ` [RFC,PATCH 2/2] perf, x86: Utilize the LBRs for machine/oops debugging Peter Zijlstra
2010-03-29 12:47 ` Stephane Eranian
2010-03-29 14:13 ` Peter Zijlstra [this message]
2010-03-29 14:20 ` Stephane Eranian
2010-03-29 17:02 ` Ingo Molnar
2010-03-29 17:12 ` Peter Zijlstra
2010-04-02 20:44 ` Ingo Molnar
2010-03-29 13:08 ` [PATCH 0/2] perf: Use LBR " Andi Kleen
2010-03-29 13:16 ` Stephane Eranian
2010-03-29 14:14 ` Peter Zijlstra
2010-03-29 20:09 ` Andi Kleen
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