Re: [RFC][PATCH] Faster generic_fls

From: Willy Tarreau (willy@w.ods.org)
Date: Thu May 01 2003 - 19:10:50 EST


On Fri, May 02, 2003 at 01:27:16AM +0200, Thomas Schlichter wrote:
 
> So for me the table version seems to be the slowest one. The BSRL instruction
> on the K6-III seems to be very slow, too. The tree and my shift version are
> faster than the original version here...
>
> That someone else can test my fls_shift version I'll provide it here again:

That's interesting Thomasr. I get 18.4 s on the Athlon here vs 32.3 for Daniel's
(I have broken my function at the moment so I cannot re-bench it right now, but
it should be near Daniel's). At first, I thought you had coded an FFS instead of
an FLS. But I realized it's valid, and is fast because one half of the numbers
tested will not even take one iteration.

Regards,
Willy

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/



This archive was generated by hypermail 2b29 : Wed May 07 2003 - 22:00:14 EST