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SubjectRe: [PATCH 4/7] perf, tool: Handle endianity swap on sample_id_all header data
On 5/16/12 12:59 AM, Jiri Olsa wrote:
> Adding endianity swapping for event header attached via sample_id_all.
>
> Currently we dont do that and it's causing wrong data to be read when
> running report on architecture with different endianity than the record.
>
> Note, running following to test perf endianity handling:
> test 1)
> - origin system:
> # perf record -a -- sleep 10 (any perf record will do)
> # perf report> report.origin
> # perf archive perf.data
>
> - copy the perf.data, report.origin and perf.data.tar.bz2
> to a target system and run:
> # tar xjvf perf.data.tar.bz2 -C ~/.debug
> # perf report> report.target
> # diff -u report.origin report.target
>
> - the diff should produce no output
> (besides some white space stuff and possibly different
> date/TZ output)
>
> test 2)
> - origin system:
> # perf record -ag -fo /tmp/perf.data -- sleep 1
> - mount origin system root to the target system on /mnt/origin
> - target system:
> # perf script --symfs /mnt/origin -I -i /mnt/origin/tmp/perf.data \
> --kallsyms /mnt/origin/proc/kallsyms
> - complete perf.data header is displayed
>
> Signed-off-by: Jiri Olsa<jolsa@redhat.com>

The code change is fine, but the commit message could use some
additions: for example, what does the current output look like and how
does the patch change it.

For example, perf is currently able to process 32-bit PPC samples on
32-bit and 64-bit x86 -- that's the use case I have and it works. So an
example of the affects of this patch for the commit log would be helpful.

Code wise:
Reviewed-by and Tested-by: David Ahern <dsahern@gmail.com>


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