Re: linux-kernel-digest V1 #113

[Robert Dinse]

On Thu, 27 Jan 2000 Larry McVoy <[e-mail]> wrote:
> 
> : Cache problems are important, but so is effective code and good
> : algorithms. Of course, it's a pretty secure stance - can't add any new
> : things because they will increase cache misses. But an extra kilobyte
> : (probably less) isn't going to matter. 
> 
> The hell it doesn't.  If I have an application that manages to the
> working set in the on chip cache, and you increase the kernel's
> use of that on chip cache by 1K, you just blew the application out
> of the cache.

     I hate to jump into this, but I also hate to see this scheduler idea
ditched for invalid reasons.

     The code isn't going to get into the cache and displace your application
just because it exists in the kernel.  To get into the cache it actually has to
be fetched. 

     Since the scheduler is adaptive, the new code, other than the test, is
only going to executed under the heavy load conditions.  Surely the test isn't
1kbyte or anywhere close to it?