Subject: Re: New device buffer queue strategy
To: Thor Lancelot Simon <>
From: Manuel Bouyer <>
List: current-users
Date: 09/02/2002 21:01:30
On Mon, Sep 02, 2002 at 01:32:35PM -0400, Thor Lancelot Simon wrote:
> [...]
> Finally, I wonder if it might make sense to attempt to merge adjacent
> requests up to MAXPHYS at queue insert time.  Given fixed (and substantial!)
> command overhead, simply reducing the number of I/O requests might help
> more than one might think, particularly with request sources such as
> RAIDframe that are known to produce smaller requests than the disks can
> handle.

I think we also should change MAXPHYS to a dynamic, per-driver value.
For IDE MAXPHYS can't be highter than 64k, but it can be much highter for
I did some work on this some time ago, I'll try to update it for UBC
and propose it for commit.

Manuel Bouyer <>