Re: [RFC] lib/vsprintf.c: Even faster decimal conversion

From: Rasmus Villemoes
Date: Tue Mar 10 2015 - 08:58:07 EST


On Tue, Mar 10 2015, Tejun Heo <tj@xxxxxxxxxx> wrote:

> Hello,
>
> On Tue, Mar 10, 2015 at 11:47:47AM +0100, Rasmus Villemoes wrote:
>> I can't explain why num_to_str apparently becomes slightly slower (the
>> patch essentially didn't touch it), but the put_dec_ helpers in any case
>> make up for that.
>
> Unrelated code changes affecting performance in seemingly random way
> isn't too uncommon. A lot of it arises from cacheline behaviors. The
> effect is sometimes surprisingly big.
>
> Generally looks pretty good to me.

Thanks.

> Andrew, can you please pick this patch up?

No, please give me a day or two to post a new version (I purposely wrote
not-yet-signed-off-by because I want to clean up both the patch and the
commit message - I just wanted to get the code out there early in the
release cycle).

Rasmus
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