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Slow your image to a crawl with this one weird trick!

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Slow your image to a crawl with this one weird trick!

"Try this one wierd trick"

Object subclass: #Foo
          instanceVariableNames: ''
          classVariableNames: 'PageId PageTitle Lua'
          poolDictionaries: ''
          category: 'Foo-Bar'.

"Open a browser and highlight the Foo-Bar category. Then.."

1 to:3000 do: [:each | | newclassname|
    newclassname := ('FooBar', each asString) asSymbol.
     Foo subclass: newclassname
          instanceVariableNames: ''
          classVariableNames: ''
          poolDictionaries: ''
          category: 'Foo-Bar']

"Your system should slow to a crawl.
Be patient and click off of the 'Foo-Bar' category and the system should free up.

Now open a HierarchyBrowser on Foo
Things will continue to work smoothly.

Conclusion? Something funky with Browser.
"

Foo allSubclasses do: [:each |
Smalltalk removeClassNamed: (each name)
]
Smalltalk removeClassNamed: #Foo
ClassOrganizer removeCategory:'Foo-Bar'

Motivation.

I am on a "import that as a class" kick for SeasideDock and the WikitextParser I am working on.

I am comfortable working with these classes as I have learned to NEVER open certain categories and use the HierarchyBrowser when I need to scan the classes therein.

Thought somebody might be intrigued with the "Why" of this on purely technical grounds. I am not that guy (:

cheers.

marcel.taeumel

Re: Slow your image to a crawl with this one weird trick!

Hmm... HierarchyBrowser has a cache in #classList. Browser has no such cache. Browser >> #hierarchicalClassList is slow.

Also, class compilation is so slow because of SmalltalkImage >> #logChange:.

84.7% {13730ms} SmalltalkImage>>logChange:

84.6% {13718ms} SmalltalkImage>>forceChangesToDisk

79.6% {12899ms} MultiByteFileStream(StandardFileStream)>>close

|79.6% {12899ms} MultiByteFileStream(StandardFileStream)>>unregister

4.9% {798ms} SecurityManager class>>default

Best,

Marcel

Am 22.08.2019 18:45:43 schrieb gettimothy via Squeak-dev <[hidden email]>:
"Try this one wierd trick"

Object subclass: #Foo
          instanceVariableNames: ''
          classVariableNames: 'PageId PageTitle Lua'
          poolDictionaries: ''
          category: 'Foo-Bar'.

"Open a browser and highlight the Foo-Bar category. Then.."

1 to:3000 do: [:each | | newclassname|
    newclassname := ('FooBar', each asString) asSymbol.
     Foo subclass: newclassname
          instanceVariableNames: ''
          classVariableNames: ''
          poolDictionaries: ''
          category: 'Foo-Bar']

"Your system should slow to a crawl.
Be patient and click off of the 'Foo-Bar' category and the system should free up.

Now open a HierarchyBrowser on Foo
Things will continue to work smoothly.

Conclusion? Something funky with Browser.
"

Foo allSubclasses do: [:each |
Smalltalk removeClassNamed: (each name)
]
Smalltalk removeClassNamed: #Foo
ClassOrganizer removeCategory:'Foo-Bar'

Motivation.

I am on a "import that as a class" kick for SeasideDock and the WikitextParser I am working on.

I am comfortable working with these classes as I have learned to NEVER open certain categories and use the HierarchyBrowser when I need to scan the classes therein.

Thought somebody might be intrigued with the "Why" of this on purely technical grounds. I am not that guy (:

cheers.

t

Levente Uzonyi

Re: Slow your image to a crawl with this one weird trick!

On Fri, 23 Aug 2019, Marcel Taeumel wrote:

> Hmm... HierarchyBrowser has a cache in #classList. Browser has no such cache. Browser >> #hierarchicalClassList is slow.
> Also, class compilation is so slow because of SmalltalkImage >> #logChange:.

I'm not sure that's true. It seems to be more like a mismeasurement by the
profiler. The following takes ~200ms on my machine (it should remove the
spam from the changes file, but use at your own risk):

| startPosition |
startPosition := (SourceFiles at: 2) size.
[ 10000 timesRepeat: [ Smalltalk logChange: 'test' ] ] timeProfile.
(SourceFiles at: 2) truncate: startPosition.

Also, #forceChangesToDisk's trick to force write-to-disk by closing and
reopening the file won't work in modern OSes. They'll realize that you're
reopening a file already in your process's cache, and will just provide
you with the cached file without forcing the contents to be written to
disk.
We have #sync to actually force write-to-disk, but using that in
#forceChangesToDisk will make the above snippet 250x slower (or more if
your storage device is not that fast).

Levente

>
> 84.7% {13730ms} SmalltalkImage>>logChange:
> 84.6% {13718ms} SmalltalkImage>>forceChangesToDisk
> 79.6% {12899ms} MultiByteFileStream(StandardFileStream)>>close
> |79.6% {12899ms} MultiByteFileStream(StandardFileStream)>>unregister
> 4.9% {798ms} SecurityManager class>>default
>
> Best,
> Marcel
>
> Am 22.08.2019 18:45:43 schrieb gettimothy via Squeak-dev <[hidden email]>:
>
> "Try this one wierd trick"
>
> Object subclass: #Foo
>           instanceVariableNames: ''
>           classVariableNames: 'PageId PageTitle Lua'
>           poolDictionaries: ''
>           category: 'Foo-Bar'.
>
> "Open a browser and highlight the Foo-Bar category. Then.."
>
>
> 1 to:3000 do: [:each | | newclassname|
>     newclassname := ('FooBar', each asString) asSymbol.
>      Foo subclass: newclassname
>           instanceVariableNames: ''
>           classVariableNames: ''
>           poolDictionaries: ''
>           category: 'Foo-Bar']
>
>
> "Your system should slow to a crawl.
> Be patient and click off of the 'Foo-Bar' category and the system should free up.
>
> Now open a HierarchyBrowser on Foo
> Things will continue to work smoothly.
>
> Conclusion? Something funky with Browser.
> "
>
>
> Foo allSubclasses do: [:each |
> Smalltalk removeClassNamed: (each name)
> ]
> Smalltalk removeClassNamed: #Foo
> ClassOrganizer removeCategory:'Foo-Bar'
>
>
> Motivation.
>
> I am on a "import that as a class" kick for SeasideDock and the WikitextParser I am working on.
>
> I am comfortable working with these classes as I have learned to NEVER open certain categories and use the HierarchyBrowser when I need to scan the classes therein.
>
>
> Thought somebody might be intrigued with the "Why" of this on purely technical grounds. I am not that guy (:
>
>
> cheers.
>
> t
>
>
>
>
>
>
>
>
>

Chris Muller-3

Re: Slow your image to a crawl with this one weird trick!

On Fri, Aug 23, 2019 at 6:23 AM Levente Uzonyi <[hidden email]> wrote:

On Fri, 23 Aug 2019, Marcel Taeumel wrote:

> Hmm... HierarchyBrowser has a cache in #classList. Browser has no such cache. Browser >> #hierarchicalClassList is slow.
> Also, class compilation is so slow because of SmalltalkImage >> #logChange:.

I'm not sure that's true. It seems to be more like a mismeasurement by the
profiler. The following takes ~200ms on my machine (it should remove the
spam from the changes file, but use at your own risk):

| startPosition |
startPosition := (SourceFiles at: 2) size.
[ 10000 timesRepeat: [ Smalltalk logChange: 'test' ] ] timeProfile.
(SourceFiles at: 2) truncate: startPosition.

Also, #forceChangesToDisk's trick to force write-to-disk by closing and
reopening the file won't work in modern OSes. They'll realize that you're
reopening a file already in your process's cache, and will just provide
you with the cached file without forcing the contents to be written to
disk.
We have #sync to actually force write-to-disk, but using that in
#forceChangesToDisk will make the above snippet 250x slower (or more if
your storage device is not that fast).

Magma handles a similar issue in its need to #sync by doing it no more than every 5 seconds.

- Chris