On 06.01.2012, at 14:15, Levente Uzonyi wrote:

> On Fri, 6 Jan 2012, Bert Freudenberg wrote:
> 
>> 
>> On 23.12.2011, at 16:38, David T. Lewis wrote:
>> 
>>> On Fri, Dec 23, 2011 at 10:13:18AM -0500, David T. Lewis wrote:
>>>> On Fri, Dec 23, 2011 at 07:39:41AM -0500, Bob Arning wrote:
>>>>> I've seen suspicious behavior (tough time interrupting and lots of
>>>>> finalization in MessageTally reports) in my 4.2 image, so I thought I'd
>>>>> look at applying this fix. One thing I'm a little puzzled about:
>>>>> HasNewFinalization is false in my image (I'm using a Cog that's a few
>>>>> months old). Under what conditions is it true?
>>>> 
>>>> I think you have spotted a timing problem here. I put the initTestPair
>>>> and checkTestPair calls together in a startUp: method, which is
>>>> wrong because it does not give the VM an opportunity to do its
>>>> updates, so the results of the test are not valid.
>>>> 
>>>> This is not exactly elegant, but if you force a garbage collection
>>>> between initTestPair and checkTestPair, the test will work properly.
>>>> 
>>>> WeakArray class>>startUp: resuming
>>>> 	resuming ifFalse: [ ^self ].
>>>> 	"Check if new finalization is supported by the VM"
>>>> 	WeakFinalizationList initTestPair.
>>>> 	Smalltalk garbageCollect.
>>>> 	WeakFinalizationList checkTestPair.
>>>> 	self restartFinalizationProcess.
>>>> 
>>>> A better fix is needed - sorry about that. I'm not sure if I'll
>>>> have a chance to look at this today, but the important thing is
>>>> to arrange for the check to be done when the image is started,
>>>> but not to continue repeating the test after it has been
>>>> successfully performed.
>>> 
>>> The following seems to take care of the issue without requiring
>>> anything to be done in the startUp: method.
>>> 
>>> WeakArray class>>finalizationProcess
>>>   | initialized |
>>>   initialized := false.
>>>   [FinalizationSemaphore wait.
>>>   initialized ifFalse: ["check VM capability once at image startup time"
>>>     WeakFinalizationList initTestPair.
>>>     Smalltalk garbageCollect.
>>>     WeakFinalizationList checkTestPair.
>>>     initialized := true].
>>>   FinalizationLock critical:
>>>     [FinalizationDependents do:
>>>       [ :weakDependent |
>>>       weakDependent ifNotNil:
>>>         [weakDependent finalizeValues]]]
>>>     ifError:
>>>     [:msg :rcvr | rcvr error: msg]] repeat
>>> 
>>> I'll update this in the inbox. Bob, thanks for catching the error.
>>> 
>>> Dave
>> 
>> 
>> 
>> Guess we should resume this discussion:
>> 
>> This is in trunk now, but if I uncomment the workaround in #openInterrupt:onProcess: I still can't break into 100000 factorial.
> 
> Do you mean that it still interrupts the finalization process first?

No, I don't get a debugger to open at all, even if I press cmd-. multiple times. Do I need a later VM?

Croquet Closure Cog VM [CoInterpreter VMMaker.oscog-eem.128] Croquet Cog 4.0.0
Mac OS X built on Sep 28 2011 13:20:56 Compiler: 4.2.1 (Apple Inc. build 5666) (dot 3)
platform sources revision r2496 http://www.squeakvm.org/svn/squeak/branches/Cog
CoInterpreter VMMaker.oscog-eem.128 uuid: 314823f6-cd6c-468f-9183-843b558f630b Sep 28 2011

- Bert -