[squeak-dev] Migrating from SharedQueue to SharedQueue2? (Mantis http://bugs.squeak.org/view.php?id=1375)

H. Hirzel hannes.hirzel at gmail.com
Fri Sep 22 10:48:02 UTC 2017


Tobias,

The SharedQueue2 class comment: time stamp is 25th June 2005; author ls.


An implementation of a shared queue based on class Monitor.  Clients
may may place items on the queue using nextPut: or remove them using
methods like next or nextOrNil.  Items are removed in first-in
first-out (FIFO) order.  It is safe for multiple threads to access the
same shared queue, which is why this is a "shared" queue.

[monitor] is used to synchronize access from multiple threads.

[items] is an ordered collection holding the items that are in the
queue.  New items are added  at the end, and old items are removed
from the beginning.

All methods must hold the monitor while they run.

-----------------------------------
Other time stamps
'From Squeak6.0alpha of 18 September 2017 [latest update: #17390] on
22 September 2017 at 12:43:13 pm'!
!SharedQueue2 methodsFor: 'accessing' stamp: 'ul 10/15/2010 08:24'!
!SharedQueue2 methodsFor: 'accessing' stamp: 'ls 6/25/2005 14:00'!
!SharedQueue2 methodsFor: 'accessing' stamp: 'nice 12/26/2009 21:34'!
!SharedQueue2 methodsFor: 'accessing' stamp: 'ul 10/15/2010 08:23'!
!SharedQueue2 methodsFor: 'accessing' stamp: 'ls 6/25/2005 14:00'!
!SharedQueue2 methodsFor: 'accessing' stamp: 'ul 10/15/2010 08:23'!
!SharedQueue2 methodsFor: 'accessing' stamp: 'ls 6/25/2005 14:01'!
!SharedQueue2 methodsFor: 'initializing' stamp: 'ls 6/25/2005 13:48'!
!SharedQueue2 methodsFor: 'printing' stamp: 'ls 6/25/2005 13:56'!
!SharedQueue2 methodsFor: 'size' stamp: 'ls 6/25/2005 14:03'!
!SharedQueue2 methodsFor: 'size' stamp: 'ls 6/25/2005 14:04'!
!SharedQueue2 methodsFor: '*39Deprecated' stamp: 'ls 6/25/2005 14:07'!
!SharedQueue2 methodsFor: '*39Deprecated' stamp: 'ls 6/25/2005 14:02'!
!SharedQueue2 methodsFor: 'copying' stamp: 'nice 10/5/2009 19:07'!
!SharedQueue2 class methodsFor: 'instance creation' stamp: 'ls 6/25/2005 13:53'!



On 9/22/17, H. Hirzel <hannes.hirzel at gmail.com> wrote:
> On 9/22/17, Tobias Pape <Das.Linux at gmx.de> wrote:
>>
>>> On 22.09.2017, at 12:19, H. Hirzel <hannes.hirzel at gmail.com> wrote:
>>>
>>> Thanks, Nicolas for the additional information. I think as well that
>>> it might be the best just to benefit from the work done in Pharo.
>>>
>>> I understand that you mean we should delete the class SharedQueue2 in
>>> the image and replace it with a file in from the SharedQueue class
>>> from Pharo 6 which is an updated version.
>>>
>>> BTW there are six instances of SharedQueue in a recent image and zero
>>> instances of SharedQueue2 in a current image.
>>>
>>> On the other side there is the question about the benefit of
>>> SharedQueue2 for Squeak. It seems that there were no complaints in the
>>> last 10 years about remaining with SharedQueue.
>>
>> I needed a SQ for Squeaksource in 2014, but one that is compatible with
>> a GemStone one. Essentially, I found the SharedQueue2 implementation more
>> helpful but feared that names would change in the future, hence I copied
>> the
>> whole class…
>
> OK, where did you get the copy of SharedQueue2 from?
> Compatibility with other Smalltalk dialects such as GemStone, Pharo is
> an issue of course. I do not know about Cuis.
>
>
>>
>> Best regards
>> 	-Tobias
>>>
>>> --Hannes
>>>
>>> On 9/20/17, Nicolas Cellier <nicolas.cellier.aka.nice at gmail.com> wrote:
>>>> 2017-09-20 19:56 GMT+02:00 H. Hirzel <hannes.hirzel at gmail.com>:
>>>>
>>>>> On 9/20/17, H. Hirzel <hannes.hirzel at gmail.com> wrote:
>>>>>> The Pharo list has some notes about this in March 2011 and Levente
>>>>>> was
>>>>>> involved.
>>>>>>
>>>>>> The issues are no longer accessible, e.g.
>>>>>> https://code.google.com/archive/p/pharo/issues/3342
>>>>>>
>>>>>
>>>>
>>>> The pharo issue tracker has moved to fogbugz, but one needs to register
>>>> for
>>>> accessing...
>>>> If you seek sharedQueue or SharedQueue you'll see a lot of activity
>>>>
>>>> https://pharo.fogbugz.com/f/cases/3173/SharedQueue-ENH
>>>> (was https://code.google.com/p/pharo/issues/detail?id=3125)
>>>> issue opened for tracking changes in Squeak
>>>> Igor claims its atomic-based queues are more robust under
>>>> heavy-concurrent-load
>>>>
>>>> https://pharo.fogbugz.com/f/cases/3390/have-a-look-at-sharedQueue-fixes-from-Levente
>>>> (was https://code.google.com/p/pharo/issues/detail?id=3342)
>>>> issue opened for tracking changes in Squeak
>>>> Markus said SharedQueue were replace with SharedQueue2 in Pharo
>>>> It's not easy to find in which issue this was done exactly (the close
>>>> status are unclear to me)
>>>>
>>>> https://pharo.fogbugz.com/f/cases/3482/SharedQueue-Fixes
>>>> (was https://code.google.com/p/pharo/issues/detail?id=3434)
>>>> same kind as #3173
>>>>
>>>> etc many other similar issues... and then:
>>>>
>>>> https://pharo.fogbugz.com/f/cases/4073/Integrating-Atomics
>>>> (was https://code.google.com/p/pharo/issues/detail?id=4026)
>>>> tells that atomics was integrated in Pharo 3.0 originating from
>>>> MCHttpRepository
>>>>    location: 'http://www.squeaksource.com/Atomics'
>>>>    user: ''
>>>>    password: ''
>>>>
>>>> so maybe we can just pick current Pharo version along with tests and
>>>> avoid
>>>> more archeology
>>>>
>>>> Nicolas
>>>>
>>>>> On 9/20/17, H. Hirzel <hannes.hirzel at gmail.com> wrote:
>>>>>>> Just reposting the message
>>>>>>> http://lists.squeakfoundation.org/pipermail/squeak-dev/2017-
>>>>> September/195308.html
>>>>>>> below so that it gets a proper subject line.
>>>>>>>
>>>>>>>
>>>>>>> Note: SharedQueue and SharedQueue2 are both in the image.
>>>>>>> SharedQueue2 was included into Squeak version 3.9 by MarcusDenker
>>>>>>> (10-07-2005) for further testing.
>>>>>>>
>>>>>>> Lex Spoon notes one year later that no problems have come to light.
>>>>>>> We
>>>>>>> should start migrating to this. All it requires is replacing
>>>>>>> SharedQueue by SharedQueue2.
>>>>>>>
>>>>>>> Then two years later (12-17-2008)  Keith_Hodges  proposes a
>>>>>>> migration
>>>>>>> script
>>>>>>>
>>>>>>> "fix begin"
>>>>>>> Installer mantis bug: 1375 fix: 'M1375-SharedQueue2Enable.1.cs'.
>>>>>>> WorldState initialize.
>>>>>>> EventSensor initialize.
>>>>>>> "fix end"
>>>>>>>
>>>>>>> We need somebody to have a look at this script
>>>>>>> 'M1375-SharedQueue2Enable.1.cs' if it is still good to do the task.
>>>>>>>
>>>>>>> BTW Pharo does not have two implementations of SharedQueue.
>>>>>>>
>>>>>>> HH.
>>>>>>>
>>>>>>>
>>>>>>> SharedQueue
>>>>>>> I provide synchronized communication of arbitrary objects between
>>>>>>> Processes. An object is sent by sending the message nextPut: and
>>>>>>> received by sending the message next. If no object has been sent
>>>>>>> when
>>>>>>> a next message is sent, the Process requesting the object will be
>>>>>>> suspended until one is sent.
>>>>>>>
>>>>>>> SharedQueue2
>>>>>>> An implementation of a shared queue based on class Monitor.  Clients
>>>>>>> may may place items on the queue using nextPut: or remove them using
>>>>>>> methods like next or nextOrNil.  Items are removed in first-in
>>>>>>> first-out (FIFO) order.  It is safe for multiple threads to access
>>>>>>> the
>>>>>>> same shared queue, which is why this is a "shared" queue.
>>>>>>>
>>>>>>> [monitor] is used to synchronize access from multiple threads.
>>>>>>>
>>>>>>> [items] is an ordered collection holding the items that are in the
>>>>>>> queue.  New items are added  at the end, and old items are removed
>>>>>>> from the beginning.
>>>>>>>
>>>>>>> All methods must hold the monitor while they run.
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> Levente Uzonyi
>>>>>>> <leves at caesar.elte.hu>       Wed, Sep 20, 2017 at 6:44 PM
>>>>>>> Reply-To: The general-purpose Squeak developers list
>>>>>>> <squeak-dev at lists.squeakfoundation.org>
>>>>>>> To: The general-purpose Squeak developers list
>>>>>>> <squeak-dev at lists.squeakfoundation.org>
>>>>>>> On Wed, 20 Sep 2017, H. Hirzel wrote:
>>>>>>>
>>>>>>>
>>>>>>>    On 9/20/17, Levente Uzonyi <leves at caesar.elte.hu> wrote:
>>>>>>>
>>>>>>>        These methods were there to make it possible to migrate from
>>>>>>> SharedQueue
>>>>>>>        to SharedQueue2 in a live system.
>>>>>>>
>>>>>>>
>>>>>>>    Could you please give some more background information about this
>>>>>>> migration?
>>>>>>>
>>>>>>>
>>>>>>> http://bugs.squeak.org/view.php?id=1375
>>>>>>>
>>>>>>>
>>>>>>>        That migration has not happened yet,
>>>>>>>
>>>>>>>
>>>>>>>    Is there a reason not to do it after 5 years?
>>>>>>>
>>>>>>>
>>>>>>> The mantis issue above has a few potential reasons.
>>>>>>> Another one may be that now there are other potential shared queue
>>>>>>> implementations to replace SharedQueue.
>>>>>>>
>>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>
>>>
>>
>>
>>
>


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