[Cuis] To GC or to Recycle?

[Frank Shearar]

On 19 December 2013 14:08, Casey Ransberger <casey.obrien.r at gmail.com> wrote:
> Sorry, I don't understand. Not sure what the advantages of Java and Python really are. I mean, Java is painfully limiting but well documented. It has what's probably the most strongly invested-in VM in history. Python, on the other hand, has a totally decent VM and is also very well documented.
>
> We aren't. I think that's our big weak point.
>
> But I don't think that the supposed real-time advantages of these systems exist. If they do, a cursory examination of how they're done should provide insight into how to do the same thing (with less code!) using the Squeak infrastructure.

Azul implemented a soft real-time GC for their JVM. It _can_ be done,
it's just expensive. The more important question is: why bother?
You're not implementing a rocket engine control module, you're
automating a car. In other words, we're talking about human reaction
times, and a 100 ms total complete shutdown of all processing is still
_twice as fast_ as a human's _mental_ reaction, never mind the
latencies involved in depressing brake pedals.

It's not even worth thinking about GC until you have a working
prototype that you can measure. (Because, if it turned out that
Smalltalk's GC wasn't fast enough (or Eliot's Spur, because that might
well be ready before the first prototype), your code base would be
high level and clean enough to automatically translate to something
else.)

> Because it really sounds to me like -- if you spent a bit more time reading -- you'd find that most of the obstacles you perceive between you and your goal are either a) already solved, b) non-existent, or c) the same problems everyone has, regardless of language, VM, or anything else.

This.

> Casey
>
>> On Dec 19, 2013, at 4:26 AM, Kirk Fraser <overcomer.man at gmail.com> wrote:
>>
>> For completeness another big reason for traffic accidents is socializing.  One can get so distracted by other people in the car or on cell phones that they pay too much attention to their social interaction and not enough to the road resulting in an accident.  That is an illustration of what we are talking about with Garbage Collection.  We have the dynamic of GC to clean up after playing to develop something in Smalltalk.  What if instead we ask the VM builder, Elliot, to add a switch to go from dynamic GC mode to static or compiled mode where all objects do not get GC'd but recycled?  So for example, if an application drags lots of data from disk into memory, the new data objects reuse the same object pointer headers as before?  In other words, in compiler mode there would be no new objects.
>>
>> This switch would allow Smalltalkers to play all they want creating new objects like now but when they want to deploy a time sensitive end user application like a self-driving car, they flip the switch and the VM treats the code as another language would treat .exe's.  This could in effect supply all the advantages Python, Java, and other .exe producing languages have without a lot of work except one primitive call. Plus the Smalltalk playground could become available again with another flip of the switch.
>>
>> Kirk W. Fraser