[squeak-dev] Switching to Sista bytecodes in trunk (was: The Inbox: Kernel-dtl.1310.mcz)

Nicolas Cellier nicolas.cellier.aka.nice at gmail.com
Sat Mar 7 20:19:17 UTC 2020


The adaptive optimization (inlining etc...) done at image side is called
Scorch.
Clément has prototyped it in Pharo at
http://smalltalkhub.com/#!/~ClementBera/Scorch
then at https://github.com/clementbera/Scorch
It's not advertised as ready for consumption yet.

Le sam. 7 mars 2020 à 20:45, Nicolas Cellier <
nicolas.cellier.aka.nice at gmail.com> a écrit :

> Hi all,
> I agree for moving to trunk asap.
> It must happen in early phases so that we test eagerly.
> There's a few test failing with wrong expectations now, but no
> catastrophic consequences.
>
> Le sam. 7 mars 2020 à 19:47, David T. Lewis <lewis at mail.msen.com> a
> écrit :
>
>> Hi Christoph,
>>
>> On Sat, Mar 07, 2020 at 06:11:56PM +0000, Thiede, Christoph wrote:
>> > Hi Dave, hi all,
>> >
>> >
>> > this sounds like a really interesting changeover. I have heard and
>> > read some rumors about Sista in the past, but I could not find any
>> > brief but complete summary of all the changes this will make to our
>>  existing Smalltalk system. So it would be great if you could point
>> > us to some kind of changelog.
>> >
>>
>> You can think of the bytecode set as the machine level instructions
>> that are executed by the virtual machine, analogous to the hardware
>> instructions that are executed by a CPU. Eliot has arranged for Squeak
>> (and Pharo and others) to be able to change over to an alternate
>> instruction set, sort of like changing the CPU on your computer without
>> turning the power off.
>>
>> The motivation for the new bytcodes (called Sista) is to enable certain
>> kinds of performance optimizations directly in the image. Think in
>> terms of some of the performance optimizations in the Cog/Spur VMs,
>> but now potentially being able to do it directly in the image.
>>
>> Others will have to give you the details, but that's the basic idea.
>>
>> >
>> > In what way will this affect your typical Squeak experience? What
>> > about performance? What about debugging/simulating code? As someone
>> > who did not yet deal with any VM side effects, I would be interested
>> > to hear about the practical effects you can see when playing around
>> > with Context & Compiler stuff. I read about FullBlockClosure which
>> > appears to be kind of detached of its defining method. How will this
>> > change accessing thisContext home etc. from a FullBlockClosure, for
>> > example? I read Sista stores an optimization cache between several
>> > runs. Where will this information be saved, at the image side or
>> > at the VM side?
>> >
>>
>> I cannot answer much of this, other than to say that initially you
>> should expect to see no difference in the user experience. Various
>> people have been using Sista for some time without problems, so it
>> will initially be a transparent change, with the more interesting
>> things happening in the future :-)
>>
>> Dave
>>
>>
>> > Lots of questions, maybe someone can answer a few of them :-)
>> >
>> >
>> > Best,
>> >
>> > Christoph
>> >
>> > ________________________________
>> > Von: Squeak-dev <squeak-dev-bounces at lists.squeakfoundation.org> im
>> Auftrag von David T. Lewis <lewis at mail.msen.com>
>> > Gesendet: Samstag, 7. M?rz 2020 18:29:40
>> > An: squeak-dev at lists.squeakfoundation.org
>> > Betreff: Re: [squeak-dev] Switching to Sista bytecodes in trunk (was:
>> The Inbox: Kernel-dtl.1310.mcz)
>> >
>> > I will leave this in the inbox for a couple of days, and if there are
>> > no objections I will move it to trunk.
>> >
>> > Dave
>> >
>> > On Fri, Mar 06, 2020 at 07:43:29PM -0500, David T. Lewis wrote:
>> > > The Sista bytecode set enables important reasearch and development
>> work.
>> > > Eliot and Clemont can explain better than me (apologies to Clemont
>> Bera
>> > > for using my seven-bit character set on your name).
>> > >
>> > > Squeak 5.3 is released and we are starting the new release cycle, so
>> it
>> > > is time to make Sista the default in trunk. Kernel-dtl.1310 (in the
>> inbox)
>> > > activates Sista in the package postscipt.
>> > >
>> > > Dave
>> > >
>> > > On Sat, Mar 07, 2020 at 12:29:13AM +0000, commits at source.squeak.org
>> wrote:
>> > > > David T. Lewis uploaded a new version of Kernel to project The
>> Inbox:
>> > > > http://source.squeak.org/inbox/Kernel-dtl.1310.mcz
>> > > >
>>
>>
>>
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