From: Masami Hiramatsu <mhiramat@redhat•com>
To: Ian Munsie <imunsie@au1•ibm.com>,
Heiko Carstens <heiko.carstens@de•ibm.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello•nl>,
linux-kernel@vger•kernel.org,
Arnaldo Carvalho de Melo <acme@redhat•com>,
Paul Mackerras <paulus@samba•org>,
Frederic Weisbecker <fweisbec@gmail•com>,
Ingo Molnar <mingo@elte•hu>,
linuxppc-dev@lists•ozlabs.org
Subject: Re: [PATCH v2 1/2] perf: Move arch specific code into separate arch directory
Date: Wed, 14 Apr 2010 07:46:12 -0700 [thread overview]
Message-ID: <4BC5D534.8010508@redhat.com> (raw)
In-Reply-To: <1271221600-25533-2-git-send-email-imunsie@au.ibm.com>
Ian Munsie wrote:
> From: Ian Munsie <imunsie@au•ibm.com>
>
> The perf userspace tool included some architecture specific code to map
> registers from the DWARF register number into the names used by the regs
> and stack access API.
>
> This patch moves the architecture specific code out into a separate
> arch/x86 directory along with the infrastructure required to use it.
>
> Signed-off-by: Ian Munsie <imunsie@au•ibm.com>
> ---
> Changes since v1: From Masami Hiramatsu's suggestion, I added a check in the
> Makefile for if the arch specific Makefile defines PERF_HAVE_DWARF_REGS,
> printing a message during build if it has not. This simplifies the code
> removing the odd macro from the previous version and the need for an arch
> specific arch_dwarf-regs.h. I have not entirely disabled DWARF support for
> architectures that don't implement the register mappings, so that they can
> still add a probe based on a line number (they will be missing the ability to
> capture the value of a variable from a register).
Hmm, sorry, I don't think it is a good way to go... IMHO, porting dwarf-regs.c
is so easy (you can just refer systemtap/runtime/loc2c-runtime.h), easier
than porting kprobe-tracer on another arch. And perf is a part of kernel tree.
It means that someone who are porting kprobe-tracer, he should port
dwarf-regs.c too. In that case, PERF_HAVE_DWARF_REGS flag will be used only
between those two patches in same patchset. So, I suggested you to drop dwarf
support if dwarf-regs mapping doesn't exist.
AFAIK, at this point, only s390 users are affected. I'd like to ask
them to just port a register mapping on perf and test it too.
Thank you,
--
Masami Hiramatsu
e-mail: mhiramat@redhat•com
next prev parent reply other threads:[~2010-04-14 14:43 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-04-14 5:06 perf: Split out arch specific code & improve PowerPC perf probe support Ian Munsie
2010-04-14 5:06 ` [PATCH v2 1/2] perf: Move arch specific code into separate arch directory Ian Munsie
2010-04-14 5:06 ` [PATCH v2 2/2] perf probe: Add PowerPC DWARF register number mappings Ian Munsie
2010-04-14 14:46 ` Masami Hiramatsu [this message]
2010-04-14 17:00 ` [PATCH v2 1/2] perf: Move arch specific code into separate arch directory Heiko Carstens
2010-04-14 18:49 ` Masami Hiramatsu
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