Re: [PATCH 6/7] perf, tool: Fix endianity trick for adds_featuresbitmask

[David Ahern]

On 5/23/12 11:59 AM, Jiri Olsa wrote:
> 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@xxxxxxxxx>
> > 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@xxxxxxxxx>
>
> 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@xxxxxxxxxx>

That is odd... and if you are getting that much you are ahead of me. 
When I analyze an x86_64 file on ppc32 all symbols show as 
kernel.kallsyms dso.

The patch applies cleanly for me on latest acme/core:
$ patch -p1 < perf-swap-features.patch
patching file tools/perf/util/header.c
patching file tools/perf/util/include/linux/bitops.h
patching file tools/perf/util/session.c
patching file tools/perf/util/session.h

David
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