[Gc] powerpc64 problems

skaller skaller at users.sourceforge.net
Wed Nov 23 13:20:18 PST 2005

On Wed, 2005-11-23 at 11:15 -0800, Boehm, Hans wrote:
> This seems to be getting slightly off subject, but since pauses usually
> seem to be blamed on garbage collectors :-) ... 
> > 
> > What I actually found was the data scattered all over the 
> > place. Some of the slower tests seem to hog the CPU, Linux 
> > never seemed to schedule more than about 5 processes, and the 
> > min/max times were spread over a huge range .. ;(
> > 
> It's actually not clear to me whether that's a bug or a feature.  We're
> starting to see machines with on the order of 100,000 cache lines.  At
> 100 nsecs to reload one, that comes out to potentially 10 msecs to
> reload the whole cache.  If you do that once per 10 msec time slice, it
> may start to look attractive to be a little less fair, and a little
> smarter about cache reuse.

Indeed, it is this sort of thing I am interested in measuring.

[Dual CPU dual core box on the way .. :]

> I do know that a fair amount of thought and benchmark testing went into
> the linux scheduler.

Hummm .. Linux itself is highly unsuitable for what it is used
for ..  we need RT/priority scheduling for desktops,
not 30 year old timesharing concepts.

John Skaller <skaller at users dot sf dot net>
Felix, successor to C++: https://felix.sf.net

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