Messages in this thread |  | | Date | Thu, 5 Mar 2015 11:10:51 -0500 | | From | Tejun Heo <> | | Subject | Re: [RFC] lib/vsprintf.c: Even faster decimal conversion |
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On Thu, Mar 05, 2015 at 08:03:33AM -0800, Joe Perches wrote: > On Thu, 2015-03-05 at 16:22 +0100, Rasmus Villemoes wrote: > > On Sat, Feb 21 2015, Rasmus Villemoes <linux@rasmusvillemoes.dk> wrote: > > > > > [...] decimal conversion [...] it does indeed seem like there is > > > something to be gained, especially on 64 bits. > > > > > > $ ./test64 > > > Distribution Function Cycles/conv Conv/1 sec > > > uniform([10, 2^64-1]) linux_put_dec 127.72 23047567 > > > uniform([10, 2^64-1]) rv_put_dec 60.73 45932786 > > > +/- -52.45% +99.30% > > [...] > > > 3 + neg_binom(0.50) linux_put_dec 16.85 159560933 > > > 3 + neg_binom(0.50) rv_put_dec 12.59 204607570 > > > +/- -25.31% +28.23% > > > > I'm assuming the underwhelming response means NAK. > > Dunno why you assume that, sometimes it just takes > awhile for people to look at non-critical, infrequent > optimization changes like this. > > Seems sensible enough to me though.
I'd like to see how this actually affects larger operations - sth along the line of top consumes D% less CPU cycles w/ N processes - if for nothing else, just to get the sense of scale, but given that we're already trying pretty hard to optimize the divisions there, I too don't see anything wrong with the patch. I haven't studied the code but looks sensible enough on a glance, so, FWIW,
Looks-sensible-by: Tejun Heo <tj@kernel.org>
Thanks.
-- tejun
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