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Re: [PATCH] Sparc exp(), expf() performance improvement


On 07/31/2017 03:47 PM, David Miller wrote:
> From: Patrick McGehearty <patrick.mcgehearty@oracle.com>
> Date: Mon, 31 Jul 2017 15:39:29 -0400
> 
>> This PATCH is intended to improve exp() and expf() performance on Sparc.
>> These changes will only be active on Sparc platforms and only for
>> those platforms that support HWCAP_SPARC_CRYPTO (niagara4 and later).
> 
> Can you explain which instructions exactly help make the compiled
> C code for exp() and expf() faster instead of being vague like
> this?
> 
> Wouldn't the new C code you are adding be faster on other CPUs as
> well, even without gcc generating instructions for Niagara 4 and
> later?


... I would also like to see the results of the glibc microbenchmark
*before* and *after* the patches. We have *specific* microbenchmarks
for lots of math functions.

-- 
Cheers,
Carlos.


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