[squeak-dev] Re: New scheduling policies [Was: Re: Re: Suspending process fix]

Andreas Raab andreas.raab at gmx.de
Thu Apr 30 04:17:22 UTC 2009

Hi Jecel -

That is actually great news. I had absolutely no idea that the Self 
scheduler was implemented in Self (I had naturally assumed it was 
implemented in C). The fact that it uses the same idea is a great 
validation of our thoughts here ;-) Do you by any chance know how Self 
performed in heavy process switch benchmarks? Has anyone ever assessed 
the overhead of the scheduler?

   - Andreas

Jecel Assumpcao Jr wrote:
> I am sorry that this week I won't be able to really participate in this
> thread, but I couldn't help mentioning that you guys are reinventing the
> Self scheduler and so might want to take a look at that.
> It includes a single primitive called TWAINS (transfer and wait for an
> interrupt or signal) for switching from one process to another. When
> Self starts up, it runs a single thread. At some point the scheduler is
> started - it is a process just like any other. The only thing special
> about the scheduler is that it calls the TWAINS primitives and none of
> the others ever do so. There is no protection against this, however.
> -- Jecel
> P.S.: the scheduler difference was what made a friend of mine drop
> Squeak and use Self for his PhD project several years ago

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