Subject: Re: diff to speed up fdalloc using two-level bitmaps
To: Niels Provos <provos@citi.umich.edu>
From: Lennart Augustsson <lennart@augustsson.net>
List: tech-perform
Date: 10/29/2003 02:12:24
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
> 
> An inline assembly function for finding the first zero bit in a
> word would be a great thing to have across architectures.

Thanks.  That doesn't look bad enough for me to worry.
The most common case looks identical, and then we pay an
overhead that is <15%.  I can live with that. :)

Good work!

	-- Lennart