[Vm-dev] Re: [Pharo-project] Do we have the new primitive?? [WAS] Re: IdentitySet but using #hash rather than #identityHash ?

[Igor Stasenko]

Sorry, its hard to devise what are primitive we're talking about?

if i understood correctly you need a primitive which answers an index
of element in
array, if found, and nil or 0 otherwise?

On 4 May 2012 21:07, Eliot Miranda <eliot.miranda at gmail.com> wrote:
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> On Thu, Apr 26, 2012 at 8:19 AM, Mariano Martinez Peck <marianopeck at gmail.com> wrote:
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>>>>>
>>>>> Hi Eliot/Levente. What is the status of this? Do we have already the new primitive? If true, how can we adapt LargeIdentitySet to use such new primitive?
>>>>
>>>>
>>>> AFAIK the new primitive is not implemented yet. Adding the primitive to the interpreter VM is very easy, but it seems to be a lot more complicated (to me) to add it to Cog, because the receiver can be a MethodContext which needs special handling.
>>>> I'll rewrite both LargeIdentitySet and LargeIdentityDictionary when the primitive is ready.
>>>
>>>
>>> Thanks Levente. So we should wait Eliot.
>>> I will ping again in a couple of weeks/months  ;)
>>>
>>
>> Ping. So I did it :)
>> Eliot if you tell us what it is needed maybe I can push Esteban or Igor (or me?) to do it ;)
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> Some form of accurate spec.  e.g. a simulation in Smalltalk, along with a specification of the types.  I'm not happy about the receiver being a MethodContext because that means the primitive has to check argument types.  A primitive can assume the type of the receiver because the primitive can be put on a specific class in the hierarchy.  Hence  aBehavior adoptInstance: anObject is much better than anObject changeClassTo: aClass, because the former can know that the receiver is a valid behavior, and simply check that the argument is a suitable instance of the receiver, whereas the latter has to check both that aClass is a valid behavior (walking its hierarchy?  checking it has a valid methodDictionary, etc, etc) /and/ that the receiver is a suitable instance of the argument.  So if possible specify it as one or two primitives on LargeIdentitySet & LargeIdentityDictionary.
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>> Thanks!
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>>>>
>>>>
>>>>
>>>> Levente
>>>>
>>>>
>>>>>
>>>>> Thanks!
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>      Levente
>>>>>
>>>>>
>>>>>            thanks
>>>>>
>>>>>            On Fri, Dec 16, 2011 at 3:28 PM, Levente Uzonyi <leves at elte.hu> wrote:
>>>>>
>>>>>      On Fri, 16 Dec 2011, Henrik Sperre Johansen wrote:
>>>>>
>>>>>       On 16.12.2011 03:26, Levente Uzonyi wrote:
>>>>>
>>>>>
>>>>>            How about my numbers? :)
>>>>>
>>>>>            "Preallocate objects, so we won't count gc time."
>>>>>            n := 1000000.
>>>>>            objects := Array new: n streamContents: [ :stream |
>>>>>              n timesRepeat: [ stream nextPut: Object new ] ].
>>>>>
>>>>>            set := IdentitySet new: n.
>>>>>            Smalltalk garbageCollect.
>>>>>            [1 to: n do: [ :i | set add: (objects at: i) ] ] timeToRun. "4949"
>>>>>
>>>>>            set := LargeIdentitySet new.
>>>>>            Smalltalk garbageCollect.
>>>>>            [1 to: n do: [ :i | set add: (objects at: i) ] ] timeToRun. "331"
>>>>>
>>>>>            set := (PluggableSet new: n)
>>>>>              hashBlock: [ :object | object identityHash * 4096 + object class
>>>>>            identityHash * 64 ]; "Change this to #basicIdentityHash in Pharo"
>>>>>              equalBlock: [ :a :b | a == b ];
>>>>>              yourself.
>>>>>            Smalltalk garbageCollect.
>>>>>            [1 to: n do: [ :i | set add: (objects at: i) ] ] timeToRun. "5511"
>>>>>
>>>>>
>>>>>            I also have a LargeIdentityDictionary, which is relatively fast, but not
>>>>>            as fast as LargeIdentitySet, because (for some unknown reason) we don't
>>>>>            have a primitive that could support it. If we had a primitive like
>>>>>            primitive 132 which would return the index of the element if found or 0 if
>>>>>            not, then we could have a really fast LargeIdentityDictionary.
>>>>>
>>>>>
>>>>>            Levente
>>>>>
>>>>>      Hehe yes, if writing a version fully exploiting the limited range, that's
>>>>>      probably the approach I would go for as well.
>>>>> (IAssuming it's the version at http://leves.web.elte.hu/**
>>>>> squeak/LargeIdentitySet.st<http://leves.web.elte.hu/squeak/LargeIdentitySet.st>
>>>>> )
>>>>>
>>>>> Mariano commented in the version at http://www.squeaksource.com/**
>>>>> FuelExperiments <http://www.squeaksource.com/FuelExperiments> that it's
>>>>> slow for them, which I guess is due to not adopting #identityHash calls to
>>>>> #basicIdentityHash calls for Pharo:
>>>>> ((0 to: 4095) collect: [:each | each << 22 \\ 4096 ]) asSet size -> 1
>>>>> So it basically uses 1 bucket instead of 4096... Whoops. :)
>>>>>
>>>>> Uploaded a new version to the MC repository which is adapted for Pharo,
>>>>> on the same machine my numbers were taken from, it does the same test as I
>>>>> used above in 871 ms. (181 with preallocation).
>>>>>
>>>>>
>>>>> Cool. One more thing: in Squeak the method using primitive 132 directly
>>>>> was renamed to #instVarsInclude:, so now #pointsTo: works as expected. If
>>>>> this was also added to Pharo, then the #pointsTo: sends should be changed
>>>>> to #instVarsInclude:, otherwise Array can be reported as included even if
>>>>> it wasn't added.
>>>>> I'll upload my LargeIdentityDictionary implementation to the same place
>>>>> this evening, since it's still 2-3 factor faster than other solutionts and
>>>>> there seem to be demand for it.
>>>>>
>>>>>
>>>>> Levente
>>>>>
>>>>>
>>>>>      Cheers,
>>>>>      Henry
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> --
>>>>> Mariano
>>>>> http://marianopeck.wordpress.com
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> --
>>>>> Mariano
>>>>> http://marianopeck.wordpress.com
>>>>>
>>>>>
>>>
>>>
>>>
>>> --
>>> Mariano
>>> http://marianopeck.wordpress.com
>>>
>>
>>
>>
>> --
>> Mariano
>> http://marianopeck.wordpress.com
>>
>>
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>
>
> --
> best,
> Eliot
>
>



-- 
Best regards,
Igor Stasenko.