[Pharo-dev] [Pharo-users] why is adding instance variables so slow?

Stephane Ducasse stepharo.self at gmail.com
Fri Nov 17 10:31:54 EST 2017


tx guys

On Fri, Nov 17, 2017 at 10:59 AM, Pavel Krivanek
<pavel.krivanek at gmail.com> wrote:
> Hi,
>
> with Yuriy and Miroslava we have tried to finish a pull request for
> conversion of rules to Renraku. But we had to face to a strange failing
> tests. It was not clear on the first sight but these tests were failing
> because of time-outs. Then we realized that the reason for this may be in
> big amount of records in the ASTCache. After some investigation with Denis
> we discovered that the real reason is in the presence of garbageCollect call
> in PharoClassInstaller>>#migrateClasses:to:using: and the big ASTCache only
> made this call significantly slower.
>
> It looks like Denis proved that the removal of this garbageCollect call is
> safe. So we should try to remove it in Pharo 7 because it evidently makes
> performance issues.
>
> -- Pavel
>
>
> 2017-04-16 8:48 GMT+02:00 Tudor Girba <tudor at tudorgirba.com>:
>>
>> Hi,
>>
>> Please let’s move this discussion on pharo-dev. And keep going :)
>>
>> Cheers,
>> Doru
>>
>>
>>
>>
>> > On Apr 14, 2017, at 12:09 PM, Denis Kudriashov <dionisiydk at gmail.com>
>> > wrote:
>> >
>> >
>> > 2017-04-14 11:09 GMT+02:00 tesonep at gmail.com <tesonep at gmail.com>:
>> > Hi, I think the problem was not clearly explained. This is the scenario
>> > that is problematic.
>> > This scenario does not happen in the new Spur implementation of
>> > forwarding, but I think is happening in the old one.
>> >
>> > 1. You have, let's say 3 instances of ClassA.
>> > 2. You add a new instance variable to ClassA. It produces
>> >    2a. A new ClassAv2 is created with the instances variables of ClassA
>> > and the newone
>> >    2b. 3 Instances of ClassAv2 are created
>> >    2c. The values of the instance variables of ClassA are copied to the
>> > ones in ClassAv2 (the ones missing are left in nil).
>> >    2d. The 3 instances of ClassA are becomed forward to the 3 instances
>> > of ClassAv2
>> >    2e. The ClassA is becomed forward ClassAv2
>> >
>> > I still not see why my example not reflects all these steps. I checked
>> > also scenario with class becoming:
>> >
>> > c1 := Class1 new.
>> > c2 := Class2 new.
>> > c1 becomeForward: c2.
>> > Class1 becomeForward: Class2.
>> > Class2 allInstances "=>#(aClass2)"
>> >
>> > It also works in Cog
>>
>> --
>> www.tudorgirba.com
>> www.feenk.com
>>
>> "What we can governs what we wish."
>>
>>
>>
>>
>>
>




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