linux-kernel - Re: [PATCH 6/7] perf, tool: Fix endianity trick for adds

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Date:	Wed, 23 May 2012 19:59:12 +0200
From:	Jiri Olsa <jolsa@...hat.com>
To:	David Ahern <dsahern@...il.com>
Cc:	acme@...hat.com, a.p.zijlstra@...llo.nl, mingo@...e.hu,
	paulus@...ba.org, cjashfor@...ux.vnet.ibm.com, fweisbec@...il.com,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 6/7] perf, tool: Fix endianity trick for adds_features
 bitmask

On Tue, May 22, 2012 at 09:48:09AM -0600, David Ahern wrote:
> On 5/22/12 2:41 AM, Jiri Olsa wrote:
> 
> >hm, any special details for the record? because I'm sure I tested this way..
> >
> >I'll retest, thanks
> >jirka
> 
> 
> The attached fixes it.

> commit 1353676ca6551a0165df030784ada20ebea73f73
> Author: David Ahern <dsahern@...il.com>
> Date:   Tue May 22 09:40:17 2012 -0600
> 
>     perf, tool: Fix endianity swapping for adds_features bitmask
>     
>     Based on Jiri's latest attempt:
>     https://lkml.org/lkml/2012/5/16/61
>     
>     Basically, adds_features should be byte swapped assuming unsigned
>     longs are either 8-bytes (u64) or 4-bytes (u32).
>     
>     Fixes 32-bit ppc dumping 64-bit x86 feature data:
>      ========
>      captured on: Sun May 20 19:23:23 2012
>      hostname : nxos-vdc-dev3
>      os release : 3.4.0-rc7+
>      perf version : 3.4.rc4.137.g978da3
>      arch : x86_64
>      nrcpus online : 16
>      nrcpus avail : 16
>      cpudesc : Intel(R) Xeon(R) CPU E5540 @ 2.53GHz
>      cpuid : GenuineIntel,6,26,5
>      total memory : 24680324 kB
>     ...
>     
>     Verified 64-bit x86 can still dump feature data for 32-bit ppc.
>     
>     Signed-off-by: David Ahern <dsahern@...il.com>

I got the header properly displayed with this patch, but I'm getting
following diffs in the perf report output (ppc32 vs x86_64):
(after moving origin perf archive build-id cache to target system)

-     0.00%            perf  [ext4]               [k] 0x0005b318                                 
+     0.00%            perf  [ext4]               [k] .cleanup_module                            

-     0.00%             yes  [kernel.kallsyms]    [k] .sys_write                                 
+     0.00%             yes  [kernel.kallsyms]    [k] .SyS_write                                 

 ^^^ this one is particularly disturbing ;)

I guess it's unrelated to the header stuff which your patch fixes
properly I think, but I got small conflict rebasing this to current tip

Reviewed-by: Jiri Olsa <jolsa@...hat.com>
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