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

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Date:	Tue, 3 Sep 2013 13:28:44 -0700
From:	Andi Kleen <ak@...ux.intel.com>
To:	Vince Weaver <vince@...ter.net>
Cc:	Andi Kleen <andi@...stfloor.org>, mingo@...e.hu,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 5/5] perf, x86: Support Haswell v4 LBR format v2

> > +	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.

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

> 
> If you get an abort, what address appears in the record?

Abort is a jump from the abort point to the abort handler or
the HLE XACQUIRE lock instruction.

> What does it mean in regards to a branch entry to be or not be in a 
> transaction?  

When the branch is executed the CPU is in the transactional execution
state.

> 
> If you set "in transaction" does that then only record branches that are 
> in transactions? 

Yes, like all the other branch filter flags.

>  What happens if you set both in transaction and not in?

Then you get all branches.

> 
> Is there some sort of document from intel you can link to that describes 
> all of this?

http://download.intel.com/products/processor/manual/253669.pdf
Chapter 17.8

-Andi
-- 
ak@...ux.intel.com -- Speaking for myself only
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