Re: [patch v2] epoll use a single inode ...

H. Peter Anvin
2007-03-07T05:40:50Z

Linus Torvalds wrote:
>
> On Tue, 6 Mar 2007, Eric Dumazet wrote:
>> I did a user space program, attached to this mail.
>>
>> I rewrote the reciprocal_div() for i386 so that one multiply is used.
>
> Ok, this is definitely faster on Core 2 as well, so "numbers talk,
> bullshit walks". No more objections.
>
> (That said, I bet you could do even better for octal and hex numbers, so
> if you *really* want to speed things up, you should just make a
> special-case routine for each base (there's just three of them), and you
> can then also optimize the base-10 thing much better (you can do two
> digits at a time by dividing by 100, etc)
>

Of course you can do better for octal and hex -- it's just shift and mask.

Decimal is trickier; however, at least on i386 it might make sense to
divide by 100 and then use the AAM instruction, or a table lookup, to
split it into individual digits.

-hpa