[PATCH v2 1/2] powerpc/selftest: Add gettimeofday() benchmark

[Denis Kirjanov]

On 9/25/15, Gabriel Paubert <paubert at iram.es> wrote:
> On Fri, Sep 25, 2015 at 12:28:30PM +0300, Denis Kirjanov wrote:
>> On 9/25/15, Arnd Bergmann <arnd at arndb.de> wrote:
>> > On Friday 25 September 2015 14:01:39 Michael Neuling wrote:
>> >> This adds a benchmark directory to the powerpc selftests and adds a
>> >> gettimeofday() benchmark to it.
>> >>
>> >> Suggested-by: Michael Ellerman <mpe at ellerman.id.au>
>> >> Signed-off-by: Michael Neuling <mikey at neuling.org>
>> >>
>> >
>> > Any reason for keeping this powerpc specific? It seems generally
>> > useful.
>> > and portable.
>> You're right. Moreover, we can put some comment to the benchmark why
>> we've made such decision to add it (reference to the commit
>> "powerpc/vdso: Avoid link stack corruption in __get_datapage()")
>
> Why gettimeofday? Isn't clock_gettime the modern variant?

Mostly, I think, for historical reasons. Both of them are implemented
as vsyscalls (on ppc, ) so why bother?

BTW: Found an interesting vdso testsuite on github:
https://github.com/nlynch-mentor/vdsotest under GPL. Not sure if we
really need such similar thing in the kernel selftest sources.

>
> BTW: dows anyone receive 2 copies of every messge in this thread ?
>
> I do, and I suspect that this is due to the Cc: list having both
> linuxppc-dev at ozlabs.org and linuxppc-dev at lists.ozlabs.org. I removed the
> former for this reply.
>
>     Gabriel
>