On Apr 6, 2010, at 11:01 PM, Dan Ingalls wrote:
> Hi, Stef -
>
>> This is fun because I was rereading the miniimage contents and started to
>> think in terms of package reorganization to support a mini image.
>> I reread also Spoon a bit and I was looking at the nuturning.
>> Dan it would be nice if you could merge the potatoe change into Jsqueak?
>
> Potato is JSqueak. I don't get it.
I know :)
Now having two different repositories with not synchronized code is not really
good.
This is was I thought that either you put a pointer to potatoe on your page or
better you merge their changes.
>> Dan, Mariano for his PhD did some analysis about number of object used
>> during typical coding session and we got around 17 %.
>> So mariano would like to see how we can get something like LOOM to dispose
>> unused objects :)
>
> Are you aware of the work I did that enables class fault detection in Squeak?
Yes :)
MDFault that hijack the method category
> If a class has a nil methodDictionary, it causes a fault (ie it sends
> recoverFromMDFault to the class). That code then restores the MD in
> addition to any anyalysis you want. I never cleaned it up for posterity, but
> it enabled lots of interesting work...
The problem is that we did some experiences (not too advance with mathieu) and
we got all the classes touched after a couple of seconds.
> By nilling all but a few MDs, and then running some application, you
> could
> tell exactly what classes were needed and which were not.
> See the method discoverActiveClasses.
> A special feature even recorded the call stack that caused each class
> to be
> touched.
ok this one I was not aware.
> What I was doing was restructuring the entire system as a bunch of
> image segments that could be swapped out and brought in
> on demand -- a sort of user-programmable swapping memory.
What mariano did so far is to
- read all the image segments code /c included
- find it dangerous
- clean the project and etoy related code (for me the simple fact that
you have all the special cases for projects
reveals that there is a deeper fundamental problem. I do not have the
answer but normally the "swapouter" should be generic
and may be provide hooks for specific cases but not do that in the
logic itself.
- define some primitive to use the extra bit to collect some measure of
object used.
- read / understand loom + the same in Java in OOPSLA 2008
next steps
- getting married
- build some tools to collect thiner grained information
One problem we saw with IS is that as soon as you have a reference from outside
the root graph to inside your graph, this
subgraph does not get saved (because not marked) and this may led to brittle
system.
Another problem was the size of array which may be double or triple than what
you want to save mariano will be more precise than me.
> This all worked at one point. Swapping of projects was a bit flakier
> because of our weak discipline on pointer scope, but it
> even worked in many cases.
>
> Where I was going with the whole "reorganizeEverything" project was that the
> SystemDictionary would be partitioned into many separate dictionaries in each
> project, and that namespaces would be the same as the project swapping unit,
> and the whole thing would be simple and fast. It actually worked once (;-)
> also.
this is interesting. I'm not convinced that I would unify namespace and project
(but this is the case in a module system).
Now the question is how to dynamically modularize a system. Because are static
organization (which are good for code management) doomed to failed
when we look at them from a use point of view?
>
> Loom was cool, but it could never come close to the speed of imageSegments.
> I played around with swapping out the entire VM Support category with all
> classes and methods, and it would swap in the entirety in less than 200
> milliseconds, and this was a decade ago.
>
> Sorry for the long digression, but maybe some of this thinking or even the
> actual mechanism can be of use to your experiments.
Yes now we were thinking that imageSegments should not rely on the internal C
organization of objects.
>
> - Dan
>
>>
>>> James Ladd <[email protected]> wrote...
>>>>> Hi Pharo-ites,
>>>>>
>>>>> I'm working on a port of Pharo to the Java Virtual Machine called Redline
>>>>> Smalltalk.
>>>>> (read more here: http://jamesladdcode.com/?p=323)
>>>>>
>>>>> I'm wanting to port every single class over time, but initially enough to
>>>>> get the
>>>>> compiler working and have a minimum runtime.
>>>>>
>>>>> Of the 1600+/- classes which are those necessary to make a small workable
>>>>> compiler
>>>>> and runtime environment?
>>>
>>> Hi, James -
>>>
>>> Bert Freudenberg forwarded this along to me, as I'm not on a Pharo mailing
>>> list.
>>>
>>> I think you know of my JSqueak project (a.k.a. Potato) -- a Squeak VM
>>> written in Java. The image that I used with it, is the same that I always
>>> use for this kind of experiment -- mini.image built in Squeak 2.2.
>>>
>>> The reason it is so cool is that it includes browser, editor, compiler,
>>> inspector debugger, and files -- everything you need for self-support.
>>> Plus it has the decompiler, and special temp-name hack, so you can actually
>>> browse sources with temp names before any file system works. My favorite
>>> thing about this image is that although it is only 600k, if you decompile
>>> all its sources, it comprises over 850k of Smalltalk, so it's like a
>>> compressed version of the sources with a full-function IDE thrown in for
>>> free ;-).
>>>
>>> As I said, the image is about 600k, of which 240k is code -- 202 classes
>>> (x2 if you count the metas) with 4590 methods. This should be a good guide
>>> for you in choosing classes to start with.
>>>
>>> You can actually run this image live in JSqueak on the web if you have Java
>>> installed and the planets are aligned correctly...
>>> http://Weather-dimensions.com/Dan/JSqueak.jnlp
>>> Another interesting statistic is that the Java .jar file is only 433k,
>>> including not only the VM, but also the entire image! This is possible
>>> because the image is so small that the pointers in it are mostly zeroes, so
>>> it compresses nicely. I just checked that this runs, and was happy to see
>>> that it putts along at 21 million bytecodes/sec on my laptop.
>>>
>>> I haven't looked recently, but I think you'll find Mini2.2.image or
>>> something like it in the same place where all the historical releases of
>>> Squeak are kept. Let me know if you can't find it.
>>>
>>> Have fun with your project! I hope this helps
>>>
>>> - Dan
>>> _______________________________________________
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>>
>>
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