This is the mail archive of the libc-alpha@sourceware.org mailing list for the glibc project.


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]
Other format: [Raw text]

Re: [PATCH] x86-64: Add sinf with FMA


On 8 Dec 2017, H. J. Lu spake thusly:

> On Fri, Dec 8, 2017 at 8:07 AM, Arjan van de Ven <arjan@linux.intel.com> wrote:
>> On 12/8/2017 8:02 AM, Nick Alcock wrote:
>>>
>>> On 4 Dec 2017, H. J. Lu uttered the following:
>>>
>>>> On Skylake, bench-sinf reports performance improvement:
>>>>
>>>>              Before        After         Improvement
>>>> max        153.996       100.094           54%
>>>> min        8.546         6.852             25%
>>>> mean       18.1223       14.4616           25%
>>>>
>>>> Any comments?
>>>
>>>
>>> Do we have any benchmark runs on older processors? They're not remotely
>>> obsolete: Intel is still selling Broadwell server parts, and the vast
>>> majority of SSE2-capable parts out there at present are not as new as
>>> Skylake.
>>
>> (oh and Haswell & Broadwell also support FMA already)

Yeah, I guess I was wondering if the speedup was actually due to FMA or
some other microarchitectural variation which might not be present on
older FMA-capable processors.

But my worries were for naught:

>     "max": 450.098,
>     "min": 8.091,
>     "mean": 18.2481

>     "max": 173.855,
>     "min": 7.253,
>     "mean": 14.2942

That's a nice speedup! :)


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]