From: Andi Kleen <andi@firstfloor.org>
To: Milian Wolff <milian.wolff@kdab.com>
Cc: Andi Kleen <andi@firstfloor.org>,
5A@linux.intel.com, linux-perf-users@vger.kernel.org
Subject: Re: LBR unwinding for user defined dynamic trace point
Date: Wed, 16 Sep 2015 20:56:14 +0200 [thread overview]
Message-ID: <20150916185614.GF1747@two.firstfloor.org> (raw)
In-Reply-To: <3862406.HVDrYIDCMl@milian-kdab2>
On Wed, Sep 16, 2015 at 11:55:22AM +0200, Milian Wolff wrote:
> On Tuesday, September 15, 2015 7:02:37 AM CEST Andi Kleen wrote:
> > Milian Wolff <milian.wolff@kdab.com> writes:
> > > When I do the same with the Dwarf unwinder, it works just fine. Using the
> > > LBR unwinder with a performance counter like instructions also works
> > > fine. Does anyone know what the issue is here?
> >
> > LBR is only supported for PMU sampling at this point.
>
> OK, thanks. Can you give me some more information on why that is? Is it
> fundamentally not possible, or simply not yet implemented?
For LBR callgraph it could be implemented. For some other LBR usages
there would be limitations, as there is no LBR freezing for software
trace points.
-Andi
--
ak@linux.intel.com -- Speaking for myself only.
next prev parent reply other threads:[~2015-09-16 18:56 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-09-15 13:12 LBR unwinding for user defined dynamic trace point Milian Wolff
2015-09-15 14:02 ` Andi Kleen
2015-09-16 9:55 ` Milian Wolff
2015-09-16 18:56 ` Andi Kleen [this message]
2016-04-07 15:05 ` Milian Wolff
2016-04-07 15:55 ` Andi Kleen
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