[PATCH] [RFC] powerpc: Add VDSO version of time

Adhemerval Zanella azanella at linux.vnet.ibm.com
Sat Apr 6 05:49:53 EST 2013


On 04/05/2013 03:21 AM, Michael Ellerman wrote:
> On Tue, Mar 19, 2013 at 04:55:31PM -0300, Adhemerval Zanella wrote:
>> Hi all,
>>
>> This patch implement the time syscall as vDSO. I have a glibc patch
>> to use it as IFUNC (as latest gettimeofday patch). Below the perf
>> numbers:
>>
>> Baseline PPC32: 380 nsec
>> Baseline PPC64: 352 nsec
>> vdso PPC32:      20 nsec
>> vdso PPC64:      20 nsec
>>
>> I focused on 64 bit kernel, do I need to provide a scheme for 32 bits
>> as well?
> You did provide a 32-bit implementation. I take it you haven't tested
> that though? Can you test it?
I haven't test it yet and I believe it won't be troublesome to do so.
>
> What happens if I don't have the glibc patch?
GLIBC current behavior is to use the syscall.

>
> cheers
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