Re: [PATCH] perf: make perf.data more self-descriptive (v4)

[Stephane Eranian]

On Fri, Sep 16, 2011 at 4:37 PM, Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:
> On Fri, 2011-09-16 at 16:35 +0200, Stephane Eranian wrote:
>> On Mon, Sep 12, 2011 at 4:43 PM, Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:
>> > On Mon, 2011-09-12 at 16:40 +0200, Stephane Eranian wrote:
>> >> I don't think this should be the test to detect endianess.
>> >
>> > You should be able to tell the endianness from the PERF_MAGIC string, it
>> > stores the string as a u64, so depending on endianness it reads back as
>> > either: PERFFILE or ELIFFREP or whatever the bswap64 result is.
>> >
>>
>> I believe in big endian, if you do od -c perf.data | head -1, you also see:
>>
>> 0000000 Â P Â E Â R Â F Â F Â I Â L Â E Â h Â\0 Â\0 Â\0 Â\0 Â\0 Â\0 Â\0
>
> Sure, but all you need to know is if the file you're reading is a
> different endian than your box, if it is swap stuff, if its not, you're
> good.

We agree on that. I am just saying the MAGIC string as it is today
may not be enough to tell us that.

>
>
>
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