Subject: Re: UBC, interactive performance, etc
To: None <eeh@netbsd.org>
From: Thor Lancelot Simon <tls@rek.tjls.com>
List: tech-kern
Date: 04/04/2001 15:29:30
On Wed, Apr 04, 2001 at 06:42:25PM -0000, eeh@netbsd.org wrote:
>
> I think this is the problem. We don't seem to make a difference between
> recently-used pages for a file we are writing, and recently-used pages
> by text or data process. When writing a large file I guess the most recently
> used pages are the ones for the file's data, and the pagedaemon free pages of
> programs instead. Maybe the pagedaemon should first free pages of file
> data ?
>
> That's also done by my patch. (At least that's what I thought when I wrote
> the patch.) Pages are immediately cleaned and put onto the idle list. Of
> course this implementation could cause other performance problems, like
> multiple writes of the same page, and does chew up lot's of CPU time.
Doesn't this also basically defeat the write-behind nature of the buffer
cache and make all I/O if not synchronous, quite close to it?
--
Thor Lancelot Simon tls@rek.tjls.com
And now he couldn't remember when this passion had flown, leaving him so
foolish and bewildered and astray: can any man?
William Styron