Re: [PATCH 5/5] perf, x86: Support Haswell v4 LBR format v2

[Vince Weaver]

On Tue, 3 Sep 2013, Andi Kleen wrote:

> > > +	PERF_SAMPLE_BRANCH_ABORT_TX	= 1U << 7, /* transaction aborts */
> > > +	PERF_SAMPLE_BRANCH_IN_TX	= 1U << 8, /* in transaction */
> > > +	PERF_SAMPLE_BRANCH_NO_TX	= 1U << 9, /* not in transaction */
> > 
> > so if you specify these flags in branch_sample_type, what information
> > appears in the branch record?  
> 
> This is just a filter, so when set branches that do not satisfy
> the filter are not reported.

Is the implementation a direct mapping to the LBR documentation or has it 
been generic so non-Intel architectures can use it?

> The patches to export the new fields haven't been merged yet.

What does this mean?  The above values are exported as part of 
  include/uapi/linux/perf_event.h
Do they not work yet?

> >  What happens if you set both in transaction and not in?
> 
> Then you get all branches.

so what happens if you set neither "PERF_SAMPLE_BRANCH_IN_TX" nor
"PERF_SAMPLE_BRANCH_NO_TX"?  Logically you'd get no branches at all,
but that can't be true as all code prior to 3.11 didn't set those values.

Vince
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/