linux-kernel - Re: [PATCHv6 2.6.35-rc3-tip 10/12] perf: Dont adjust symbols on name lookup

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Message-ID: <20100629175342.GE23231@linux.vnet.ibm.com>
Date:	Tue, 29 Jun 2010 23:23:42 +0530
From:	Srikar Dronamraju <srikar@...ux.vnet.ibm.com>
To:	Arnaldo Carvalho de Melo <acme@...radead.org>
Cc:	Peter Zijlstra <peterz@...radead.org>, Ingo Molnar <mingo@...e.hu>,
	Masami Hiramatsu <mhiramat@...hat.com>,
	Mel Gorman <mel@....ul.ie>,
	Randy Dunlap <rdunlap@...otime.net>,
	Steven Rostedt <rostedt@...dmis.org>,
	Roland McGrath <roland@...hat.com>,
	"H. Peter Anvin" <hpa@...or.com>,
	Christoph Hellwig <hch@...radead.org>,
	Ananth N Mavinakayanahalli <ananth@...ibm.com>,
	Oleg Nesterov <oleg@...hat.com>,
	Mark Wielaard <mjw@...hat.com>,
	Mathieu Desnoyers <mathieu.desnoyers@...icios.com>,
	LKML <linux-kernel@...r.kernel.org>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Frederic Weisbecker <fweisbec@...il.com>,
	Jim Keniston <jkenisto@...ux.vnet.ibm.com>,
	"Rafael J. Wysocki" <rjw@...k.pl>,
	"Frank Ch. Eigler" <fche@...hat.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	"Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>
Subject: Re: [PATCHv6 2.6.35-rc3-tip 10/12]  perf: Dont adjust symbols on
 name lookup

> > 
> > perf: Dont adjust symbols on name lookup
> > 
> > Adjusting symbols is not needed if we are searching by name even
> > if the symbols correspond to user space objects.
> > Infact if we adjust and search symbols by name, we get incorrect
> > results.
> 
> I'll review this, but it would be nice to explain why we get incorrect
> results, as we may be just fixing a symptom of some other problem.
> 

You are right. I removed this patch and still see no change in
behaviour. Earlier without this patch, I saw that perf report
would show a wrong function name(around 2.6.34-rc5 and I carried it
to 2.6.35-tip). However the number of events recorded would
correspond to the probed function. 

Since I am seeing correct behaviour even without this patch, I
will drop this patch in the next posting of the patchset.

--
Thanks
Srikar
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