Subject: Re: diff to speed up fdalloc using two-level bitmaps
To: Lennart Augustsson <lennart@augustsson.net>
From: David Laight <david@l8s.co.uk>
List: tech-perform
Date: 10/28/2003 18:08:26
On Tue, Oct 28, 2003 at 11:25:59AM -0500, Niels Provos wrote:
> On Tue, Oct 28, 2003 at 01:40:08PM +0100, Lennart Augustsson wrote:
> > Could you show the graph for just < 100 fds?
> > That's after all where most of us live. :)
> 
> It could need some fine tuning
> 
>  http://www.citi.umich.edu/u/provos/benchmark/netbsd-fdalloc-zoom.jpg

Have you factored out the cost of gettimeofday()?

> An inline assembly function for finding the first zero bit in a
> word would be a great thing to have across architectures.

A standard name for something that if probably inlined...

Anyone know the execution time for bsf on anything new?
It wouldn't surprise me if it is microcoded - so an expanded
function might be quicker!
(especially in a benchmark where the code/data will be cached!)

	David

-- 
David Laight: david@l8s.co.uk