Re: [PATCH] [POWERPC] Use a sensible default for clock_getres() inthe vdso.

From: Chirag Jog
Date: Tue Feb 05 2008 - 04:08:33 EST


* Tony Breeds <tony@xxxxxxxxxxxxxxxxxx> [2008-02-05 16:16:48]:

> On Sun, Jan 27, 2008 at 07:32:59PM +0530, Sripathi Kodi wrote:
> > Hi Paul,
> >
> > On PPC, I see a disparity between clock_getres implementations in the
> > vdso and syscall. I am using a IBM Openpower hardware and 2.6.24 kernel
> > with CONFIG_HIGH_RES_TIMERS=y.
> >
> > clock_getres call for CLOCK_REALTIME returns 1 millisecond. However,
> > when I edit arch/powerpc/kernel/vdso*/gettimeofday.S to force it to use
> > sys_clock_getres, I get 1 nanosecond resolution. The code in vdso seems
> > to be returning some pre-defined (incorrect) variables.
> >
> > Could you please let me know the reason for this? Is it something that
> > should be fixed in vdso?
>
> Can you try the attached patch and see it if works for you?
I tried this patch.
It seems to solve the reported problem and give a 1ns resolution.
Thanks.


--
Cheers,
Chirag Jog

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