Interval had a great submillisecond GC that was terrific for 
real-time apps. Maybe we can get this from them now that they have 
donated their work to Stanford (per Glenn Edens).

Don't forget that the current GC (and any Squeak GC) has to handle 
real time demands for animation and music, etc.

Cheers,

Alan

------

At 12:41 PM +0100 2/18/02, Marcel Weiher wrote:
>On Tuesday, January 29, 2002, at 11:15 PM, Scott A Crosby wrote:
>
>>Quick summary:
>>   The default paramaters for the GC are a poor choice for RAM-rich modern
>>computers. A 3x performance gain on GC is obtainable, if you're willing to
>>dedicate RAM to squeak. (My desktop has 768, so I think nothing of running
>>with 100-500mb)
>>
>>The current squeak GC does an incremental collection every 4000
>>allocations. Although this can lead to sub-ms latency, it is excessive,
>>especially for long running or many GUI applications.
>>
>>So, running macrobenchmarks, and counting GC time, I get:
>>
>>  22 seconds of GC time. (only GC when you absolutely must, 500mb RAM.)
>>  60 seconds of GC time. (GC every 4000 allocations)
>>+15 additional seconds of fullGC's in either case [*]
>>
>>A typical run of macrobenchmarks is about 360 seconds on the P2-450.
>>
>>I'm not sure the threshold is where GC time drops by 2/3, but the fact
>>that it does is an indication that other people can have similar gains. I
>>even see some gain at 50mb and 200kallocs/GC.
>
>Just a thought:  since the macro-benchmarks are doing full-GCs 
>between each benchmark (not timed), could it be that the performance 
>improvements are just artifacts of the benchmarking process?
>
>In essence, you're getting a GC that's 'free' between each of the 
>benchmarks.  So if you can delay the need for a GC until the end of 
>each benchmark, then you will have 0 GC overhead in the benchmarks, 
>without any accompanying real-world gain.
>
>Marcel
>
>
>--
>Marcel Weiher				Metaobject Software Technologies
>marcel at metaobject.com		www.metaobject.com
>Metaprogramming for the Graphic Arts.   HOM, IDEAs, MetaAd etc.


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