To: None <>
From: Thor Lancelot Simon <>
List: tech-kern
Date: 12/01/2003 13:35:23
On Mon, Dec 01, 2003 at 09:13:45AM -0800, Chuck Silvers wrote:
> On Mon, Dec 01, 2003 at 10:32:43AM +0100, Juergen Hannken-Illjes wrote:
> > 
> > This should never become the default. It works well on one-user, one-disk
> > desktop machines. The interactive processes are more responsive while
> > big files are written (taking a CD image for example).
> > 
> > I don't think it runs well on multi-user, multi-disk servers. As I don't
> > have this class of machines I cannot test it.
> if you haven't tested such a configuration, why do you think it doesn't
> run well?  can you give some details on what test I could run with what
> configuration to expose such problems?

I think some relevant benchmarks might be found in the original trickle-sync
paper (this policy is similar to the "read priority" they describe some
System V buffer caches implementing, with mixed results).

SGI has an interesting general-purpose policy with two queues, pulling a
configurable number of requests from each queue in turn, that is described
in the release notes for a recent version of Irix.  It appears to perform
reasonably well for both interactive and fileserver workloads and might be
a better default than either our current policy or NEW_BUFQ_STRATEGY.  I've
posted a pointer to it here before -- if anyone wants to implement this but
can't find the details I'll dig them up again.

 Thor Lancelot Simon	                            
   But as he knew no bad language, he had called him all the names of common
 objects that he could think of, and had screamed: "You lamp!  You towel!  You
 plate!" and so on.              --Sigmund Freud