Mike,

I've seen this problem on XP, too. It seems like the Windows scheduler
is _extremely_ poorly designed. I know how to solve this problem and
I'll fix it.

Cheers,
  - Andreas

> -----Ursprüngliche Nachricht-----
> Von: Mike Rutenberg [mailto:mdrs at akasta.com] 
> Gesendet: Donnerstag, 24. Januar 2002 19:00
> An: Squeak-dev at lists.squeakfoundation.org
> Cc: Andreas.Raab at gmx.de; Mike Rutenberg
> Betreff: Weird Windows 2000 scheduling behaviour with Squeak VM
> 
> 
> If I do a long Squeak calculation like
> 	[true] whileTrue: [12 / 4]
> the Windows 2000 scheduler will only occasionally give any 
> other "normal
> priority" Win32 process any CPU time.  Other processes, even those who
> are "on top", will be almost entirely deprived of cycles.  
> For example,
> the TaskManager CPU graph or list of running processes no 
> longer updates
> regularly, often pausing for 20 seconds.  Similarly 
> InternetExplorer and
> the FileManager become very unresponsive.
> 
> I have also noticed the same behavior if I compact a Celeste mail
> database (which involves lots of memory allocations and IO) 
> rather than
> an endless simple loop.
> 
> Interestingly, a second simultaneously running Squeak VM is 
> not affected
> while the first runs the endless loop.  It responds normally 
> though all
> of this, and does not seem noticeably slowed down, for 
> instance quickly
> opening a change sorter.
> 
> When I am able to finally bring up the TaskManager, I can eventually
> lower the priority of Squeak.exe and the system immediately becomes
> responsive again.
> 
> As a test, I wrote a small C program to duplicate this endless loop. 
> When I run it, the CPU meter pegs at 100%, but the system does not
> become unresponsive.
> 
> Has anyone else seen anything like this under Windows NT or 2000?  Is
> this a side effect of something done intentionally in the VM? 
>   I do not
> remember seeing problem under Windows 98.
> 
> Mike
> 
>