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From: Ingo Molnar <mingo@elte.hu>
To: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>,
	"K.Prasad" <prasad@linux.vnet.ibm.com>,
	LKML <linux-kernel@vger.kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Paul Mackerras <paulus@samba.org>
Subject: Re: [PATCH 4/4] perf tools: Add support for breakpoint events in perf tools
Date: Mon, 23 Nov 2009 22:25:01 +0100	[thread overview]
Message-ID: <20091123212501.GA18917@elte.hu> (raw)
In-Reply-To: <20091123211945.GC4979@nowhere>


* Frederic Weisbecker <fweisbec@gmail.com> wrote:

> > Using just /proc/kallsyms all we can do is find the size of a 
> > variable by looking at its address and the address of the next one.
> > 
> > - Arnaldo
> 
> Hmm, but I worry a bit about alignment which would return us the wrong 
> size.
> 
> May be can we first try to get the address from /proc/kallsyms, and if 
> we have dwarf, get the size from it, otherwise try some magic with 
> /proc/kallsysms...

Can we extend /proc/kallsyms (or add /proc/kallsyms) to include a size 
field?

Perhaps can we generate some sort of DSO-alike thing in /proc/vmlinux 
(via a default-off debug option in .config), that perf could just 
interpret the usual ELF way - which happens to be the symbol table of 
the kernel? It would use up some RAM, but it would also be quite useful 
for debugging purposes.

	Ingo

  reply	other threads:[~2009-11-23 21:25 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-11-23 14:42 [PATCH 1/4] hw-breakpoints: Include only linux/perf_event.h from kernel part of bp headers Frederic Weisbecker
2009-11-23 14:42 ` [PATCH 2/4] hw-breakpoints: Check the breakpoint params from perf tools Frederic Weisbecker
2009-11-23 17:43   ` [tip:perf/core] " tip-bot for Frederic Weisbecker
2009-11-23 14:42 ` [PATCH 3/4] perf: Add kernel side syscall events support for breakpoints Frederic Weisbecker
2009-11-23 17:43   ` [tip:perf/core] " tip-bot for Frederic Weisbecker
2009-11-23 14:42 ` [PATCH 4/4] perf tools: Add support for breakpoint events in perf tools Frederic Weisbecker
2009-11-23 17:36   ` K.Prasad
2009-11-23 20:25     ` Frederic Weisbecker
2009-11-23 21:09       ` Arnaldo Carvalho de Melo
2009-11-23 21:19         ` Frederic Weisbecker
2009-11-23 21:25           ` Ingo Molnar [this message]
2009-11-23 21:25           ` Arnaldo Carvalho de Melo
2009-11-23 17:38   ` Ingo Molnar
2009-11-23 17:44   ` [tip:perf/core] " tip-bot for Frederic Weisbecker
2009-11-23 17:43 ` [tip:perf/core] hw-breakpoints: Include only linux/perf_event.h from kernel part of bp headers tip-bot for Frederic Weisbecker

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