Re: No 100 HZ timer !

Jeff Dike
2001-04-09T17:18:45Z

schwidefsky@de.ibm.com said:
> I have a suggestion that might seem unusual at first but it is
> important for Linux on S/390. We are facing the problem that we want
> to start many (> 1000) Linux images on a big S/390 machine. Every
> image has its own 100 HZ timer on every processor the images uses
> (normally 1). On a single image system the processor use of the 100 HZ
> timer is not a big deal but with > 1000 images you need a lot of
> processing power just to execute the 100 HZ timers. You quickly end up
> with 100% CPU only for the timer interrupts of otherwise idle images.

This is going to be a problem for UML as well, and I was considering something
very similar. I did a quick scan of your prose, and the description sounds
like what I had in mind.

So, count me in as a supporter of this.

A small request: Since S/390 is not the only port that needs this, I'd be
happy if it was made as generic as possible (and it may already be, I haven't
gone through the code yet).

Jeff