Impacts of the squeak garbage collector

Scott A Crosby crosby at qwes.math.cmu.edu
Mon Feb 18 22:46:13 UTC 2002


On Mon, 18 Feb 2002 John.Maloney at disney.com wrote:

> Hi, Scott,
>
> At 3:17 PM -0500 2/18/02, Scott A Crosby wrote:

> >
> >Ah, that explains why they're so low. But, I suspect that a lot of the
> >uses of squeak are not that hard realtime, or not on that sort of
> >hardware. So, the GC parm are specifically designed for the hardest task
> >on the slowest hardware, when both of them are relatively uncommon, both
> >individually, and especially in combinations.
>
> True, but teachers and kids are not likely to have the sophistication to
> tweak GC settings, whereas the serious Smalltalkers on the Squeak list do.

I don't know if I agree. People *really* tend to leave defaults alone.

> So, if we did enough benchmarking to come up with settings for some of
> the intersting positions on your "latency vs. GC overhead" knob and
> perhaps make a little UI for selecting these settings, I think we could
> address the needs of both communities.

The GC settings are adaptively chosen so-as to make sure the average
latency is within the given target.

Then a UI for choosing the target.... Say, where the target latency is
chosen per-project. (Assume that project authors *will* correctly set the
latency for the project.)

Let the default latency target be 40ms, realtime projects set it lower,
long-time processing projects can set it to 400ms or higher.

>
> Congratulations on getting into graduate school, by the way. Where did
> you do your undergrad studies?
>

Thanks... Carnegie Mellon University

Scott




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