Re: [GIT PULL 00/16] perf/core improvements and fixes

From: Arnaldo Carvalho de Melo
Date: Tue Feb 14 2012 - 08:11:15 EST


Em Tue, Feb 14, 2012 at 11:50:18AM +0100, Joerg Roedel escreveu:
> On Mon, Feb 13, 2012 at 10:23:07PM -0700, David Ahern wrote:
> > On 2/13/12 10:10 PM, Namhyung Kim wrote:
> > >It happened because I used old kernel version that isn't aware of the
> > >exclude_guest bit. So the check on attr->__reserved_1 in
> > >core.c::perf_copy_attr() failed and then ended up seeing EINVAL at
> > >perf_evsel__open().

> > comes back to 1aed2671738785e8f5aea663a6fda91aa7ef59b5 again. See

> > https://lkml.org/lkml/2012/2/8/234

> Grr. I totally forgot that issue. Is there some way to detect the perf
> kernel-features? Otherwise the only fix seems to be to drop the patch
> changing the default. The crashes should be fixed by the other patch
> already.

Well, we need to detect it like we do with sample_id_all. In this case
we would try with exclude_guest, if it fails with EINVAL, we realise it
is not available, clean that bit and try again.

- Arnaldo
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