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Re: PowerPC: gettimeofday optimization by using IFUNC
- From: Adhemerval Zanella <azanella at linux dot vnet dot ibm dot com>
- To: Andi Kleen <andi at firstfloor dot org>
- Cc: "GNU C. Library" <libc-alpha at sourceware dot org>
- Date: Fri, 22 Feb 2013 17:28:21 -0300
- Subject: Re: PowerPC: gettimeofday optimization by using IFUNC
- References: <5127C775.1050804@linux.vnet.ibm.com> <m2sj4ow19e.fsf@firstfloor.org>
On 02/22/2013 05:18 PM, Andi Kleen wrote:
> Adhemerval Zanella <azanella@linux.vnet.ibm.com> writes:
>
>> Hi,
>>
>> This patch make gettimeofday uses IFUNC and optimizing its call by avoid
>> the unnecessary way through glibc's internal __gettimeofday. Any tips,
>> advices, comments?
> Very nice optimizations. The extra round trip always annoyed me. And
> using IFUNC for it is a nice trick. Is it possible to do on x86 too?
>
The x86_64 code already has the optimization, but afaik x86 does not provide
a vdso (well, at least I couldn't see any on a 3.2 kernel, correct me if I'm
wrong).