[squeak-dev] Are Squeak processes pre-emptive?
josh at schwa.ca
Thu Apr 15 17:10:03 UTC 2010
On Apr 15, 2010, at 10:02 AM, Eliot Miranda wrote:
> If there existed a Squeak VM which had true concurrency and could use multiple cores then a high-priority process would not necessarily preempt a lower-priority process in the first place and hence ensuring fairness would require additional implementation work. Essentially if and when Smalltalk VMs do move to true concurrency and multiple cores the scheduler will have to be rethought and rewritten and it would probably be a good idea to take the line Igor has with much more control at the image level. Note that fundamentals like Processor activeProcess would no longer work. One would need e.g. a pseudo-variable thisProcess.
> But for the moment no such Squeak VM is in existence. Those Squeak systems which do use multiple cores, Igor's Hydra, and Sam and Dave's Tilera64, replicate images so there are many green-threaded images networked together.
I don't think that this is true for the Tilera64 VM. It's been a while since I looked at the paper, but I'm pretty sure that multiple processors are operating on the same object memory. Am I mistaken?
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