RE: [patch v4 00/13] branch tracing support for Atom

Metzger, Markus T
2012-11-27T17:30:15Z

> -----Original Message-----
> From: Jan Kratochvil [mailto:jan.kratochvil@redhat.com]
> Sent: Tuesday, November 27, 2012 5:28 PM
> To: Metzger, Markus T
> Cc: gdb-patches@sourceware.org; markus.t.metzger@gmail.com; palves@redhat.com; tromey@redhat.com; kettenis@gnu.org
> Subject: Re: [patch v4 00/13] branch tracing support for Atom
>
> On Tue, 27 Nov 2012 17:16:30 +0100, Metzger, Markus T wrote:
> > Looks like it wouldn't be that difficult, after all. The assumption that
> > a ret returns to the last call we've seen might be a bit optimistic, though.
> > And we wouldn't be able to handle those cases where the call is not included
> > in the trace. The back trace would thus be rather short.
>
> In which case the call is not present in the btrace recoding? We also have
> the recording initial PC and we can also record the backtrace at that initial
> PC.

Btrace uses a ring buffer into which the h/w writes from-to records for each branch. We will only see the tail of the execution trace.

Regards,
Markus.
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