From: Anton Vorontsov <avorontsov@ru.mvista.com>
To: Steven Rostedt <srostedt@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>, Paul Mackerras <paulus@samba.org>,
linux-kernel@vger.kernel.org, linuxppc-dev@ozlabs.org
Subject: Re: [PATCH v2] ftrace: On PowerPC we don't need frame pointers for CALLER_ADDRs
Date: Tue, 3 Feb 2009 21:59:33 +0300 [thread overview]
Message-ID: <20090203185933.GA9878@oksana.dev.rtsoft.ru> (raw)
In-Reply-To: <1233678738.16878.5.camel@localhost.localdomain>
On Tue, Feb 03, 2009 at 11:32:18AM -0500, Steven Rostedt wrote:
>
> On Tue, 2009-02-03 at 19:19 +0300, Anton Vorontsov wrote:
> > On Tue, Feb 03, 2009 at 05:06:45PM +0100, Ingo Molnar wrote:
>
> > [1] Btw, why exactly do we need the -fno-omit-frame-pointer for
> > "FUNCTION_TRCER" tracer? Why just -pg isn't sufficient?..
> >
>
> The problem is this that is in the toplevel Makefile:
>
>
> ifdef CONFIG_FRAME_POINTER
> KBUILD_CFLAGS += -fno-omit-frame-pointer -fno-optimize-sibling-calls
> else
> KBUILD_CFLAGS += -fomit-frame-pointer
> endif
>
>
> -pg is incompatible with -fomit-frame-pointer
Ah...
$ gcc -pg -fomit-frame-pointer -S c.c
gcc: -pg and -fomit-frame-pointer are incompatible
It's hard-coded in gcc, in the code that don't know about
architecture details.
But on PowerPC -O1 implies -fomit-frame-pointer, that is
gcc -pg -O1 -fno-omit-frame-pointer
and
gcc -pg -O1
produce different outputs. Thus -pg -O should be the same
as "-pg -O -fomit-framepointer".
--
Anton Vorontsov
email: cbouatmailru@gmail.com
irc://irc.freenode.net/bd2
next prev parent reply other threads:[~2009-02-03 18:59 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-01-31 19:06 [PATCH] ftrace: On PowerPC we don't need frame pointers for CALLER_ADDRs Anton Vorontsov
2009-02-02 0:35 ` Benjamin Herrenschmidt
2009-02-02 14:04 ` Steven Rostedt
2009-02-03 14:56 ` [PATCH v2] " Anton Vorontsov
2009-02-03 16:06 ` Ingo Molnar
2009-02-03 16:19 ` Anton Vorontsov
2009-02-03 16:32 ` Steven Rostedt
2009-02-03 18:59 ` Anton Vorontsov [this message]
2009-02-04 0:34 ` Benjamin Herrenschmidt
2009-02-04 15:07 ` Anton Vorontsov
2009-02-04 15:08 ` [PATCH 1/3] Makefile: Include arch Makefiles as late as possible Anton Vorontsov
2009-02-04 21:26 ` Ingo Molnar
2009-02-11 3:51 ` Benjamin Herrenschmidt
2009-02-11 13:23 ` Ingo Molnar
2009-02-11 14:11 ` Steven Rostedt
2009-02-14 19:58 ` Sam Ravnborg
2009-02-14 19:57 ` Sam Ravnborg
2009-02-14 22:03 ` Ingo Molnar
2009-02-15 0:19 ` Benjamin Herrenschmidt
2009-02-15 8:09 ` Ingo Molnar
2009-02-16 14:20 ` Anton Vorontsov
2009-02-16 14:53 ` Anton Vorontsov
2009-02-16 20:04 ` Sam Ravnborg
2009-02-16 16:08 ` Anton Vorontsov
2009-02-16 17:22 ` Ingo Molnar
2009-02-04 15:08 ` [PATCH 2/3] powerpc: Make it possible to safely select CONFIG_FRAME_POINTER Anton Vorontsov
2009-02-05 0:31 ` Benjamin Herrenschmidt
2009-02-05 0:35 ` Steven Rostedt
2009-02-05 1:12 ` Anton Vorontsov
2009-02-05 1:15 ` Benjamin Herrenschmidt
2009-02-05 1:30 ` Anton Vorontsov
2009-02-05 15:45 ` Anton Vorontsov
2009-02-04 15:08 ` [PATCH 3/3] tracing: Tracers that use CALLER_ADDR macros should select FRAME_POINTER Anton Vorontsov
2009-02-04 15:26 ` Frédéric Weisbecker
2009-02-04 15:31 ` Steven Rostedt
2009-02-04 15:36 ` Anton Vorontsov
2009-02-04 16:50 ` Frédéric Weisbecker
2009-02-04 8:17 ` [PATCH v2] ftrace: On PowerPC we don't need frame pointers forCALLER_ADDRs Usha Rani Konudula
2009-02-04 8:37 ` Usha Rani Konudula
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