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) Mariano commented in the version at 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). Cheers, Henry