[Moose-dev] Re: A quick analyzis of the usage of instance variables in Moose

Wow!

Alexandre

On Mar 13, 2017, at 9:53 AM, Nicolas Anquetil Nicolas.Anquetil@inria.fr wrote:

Reviving this old mail from Guillaume.

I did an analysis on a huge model (>2M entities) we have:

• .mse file: 372.5 MB
• .image file without the model: 86.9 MB
• image with model: 692.8 MB (thus apparently 605,9 MB used by the model)

Then I did a small experiment: I removed the four instance variables of FAMIXSourcedEntity (sourceAnchor, sourceLanguage, comments, declaredSourceLanguage) and replaced them by variables in the privateState

for example:

FAMIXSourcedEntity>>comments "Returns the list of comments defined for the entity."

<MSEProperty: #comments type: #FAMIXComment opposite: #container> <multivalued> <derived>
<MSEComment: 'list of comments defined in the entity'>

^comments

becomes FAMIXSourcedEntity>>comments "Returns the list of comments defined for the entity."

<MSEProperty: #comments type: #FAMIXComment opposite: #container> <multivalued> <derived>
<MSEComment: 'list of comments defined in the entity'>
"^ comments"
^ self privateState cacheAt: #comments ifAbsentPut: nil

As a result, the .image file is 673.3 MB (thus apparently 586,4 MB used by the model) Not huge, but almost 20 MB saved, 3% of the initial memory

nicolas

On 10/11/2016 20:49, stepharo wrote:

...

Thanks

A task of Pavel will be to see how slots usage can reduce that space lost. For the empty collection having a kind of - sharing an #() in a classVar - creating a new collection on use could be a solution.

Le 7/11/16 à 12:16, Guillaume Larcheveque a écrit :

...

Hi Moose users,

as you may know, at Synectique we experiment lots of issues about memory usage. That's why i had a look at the number of unused instance variables in one of our system loaded with a big model from one of our main customer.

Total instance variables: 26.852.653 Used instance variables: 17.393.938 Empty collections: 5.023.508 Recoverable instance variables: 14.482.223

The recoverable instance variables are those with nil or an empty collection (or MultiValueLink)

As you can see, we can save a lot of memory :-)

Here is my (dirty) code to get that:

countUsedInstanceVariableInForSubInstances: aClass | usedInstNbr instNbr emptyCollNbr | usedInstNbr := 0. instNbr := 0. emptyCollNbr := 0. aClass allSubInstancesDo: [ :anEntity | instNbr := instNbr + anEntity class allInstVarNames size. anEntity class allInstVarNames doWithIndex: [ :e :i | (anEntity instVarAt: i) ifNotNil: [ :content | ([ content isEmpty. emptyCollNbr := emptyCollNbr + 1. false ] on: MessageNotUnderstood do: [ false ]) ifFalse: [ usedInstNbr := usedInstNbr + 1 ] ] ] ]. ^ {('Used instance variables' -> usedInstNbr). ('empty collections' -> emptyCollNbr). ('Recoverable instance variables' -> (instNbr - (usedInstNbr - emptyCollNbr))). ('Total instance variables' -> instNbr)}

-- Guillaume Larcheveque

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-- Nicolas Anquetil -- MCF (HDR) Project-Team RMod

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