[Xen-devel] Re: [PATCH] add timeouts to mini-os

[Robert Kaiser <rkaiser@xxxxxxxxx>]

Hi Gregor

Am Sonntag, 1. Oktober 2006 20:38 schrieb Grzegorz Milos:
> Hi Robert,
>
> Having timeout timers in MiniOS would be very useful indeed (I had a
> few people asking about that already).
>
> Timers in Xen and Linux are a bit different then your implementation
> for MiniOS (inspect xen/common/timer.c and <linux>/kernel/timer.c for
> more detail). The way that Linux/Xen handles timers is slightly more
> flexible, however the functionality that you could put in Mini-OS
> timer handler is very limited (you can only wake up a thread/set of
> threads really).

Which functionalities would you like to see that are currently missing? 

> I think we can therefore stick to this solution for 
> now. I'll have a look through the code tomorrow, and let you know if
> I have any comments.

Thanks.

(There are few shortcomings of my implementation that I'm well aware of 
myself. For instance, I think it would be more efficient to unlink blocked 
threads from the ready queue and keep the ones with pending timeouts in a 
"timeout" queue, sorted by ascending expiry date.  That way, it wouldn't be 
necessary to walk the entire ready queue all the time to see if any timeouts 
have expired: it would suffice to just look at the head of the timeout queue. 
However, my goal was to keep things simple and to not change more than 
absolutely necessary.)

Cheers

Rob

>
> Thanks.
> Gregor
>
> On 1 Oct 2006, at 00:18, Robert Kaiser (FH) wrote:
> > Hi Gregor,
> >
> > attached is a patch to mini-os. It removes the debug print of
> > current time
> > (which didnt work anyway) and adds support for timed sleeps. The
> > application
> > code now has a thread which is activated periodically (once every
> > second) by
> > means of the new sleep function and prints out the current time, so
> > the
> > program now actually does what the README says. The idle thread now
> > blocks as
> > long as necessary (i.e. until the nearest timeout expires) instead
> > if the
> > fixed 10 seconds as before.
> >
> > Please review it and consider for inclusion.
> >
> > Cheers
> >
> > Rob
> > <minios.patch>

-- 
Robert Kaiser

SYSGO AG
Office Mainz
Am Pfaffenstein 14 / D-55270 Klein-Winternheim / Germany
Tel.: +49-6136-814791 / Fax: +49-6136-9948-10
Email: robert.kaiser@xxxxxxxxx / Web: http://www.sysgo.com


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