Hmm. Looking at the results in a relatively up to date Squeak 4.5: [ 10000 timesRepeat: [ | c | c := OrderedCollection new: 100000. 1 to: 10000 do: [ :i | c add: i ] ] ] timeToRun 3624 [ 10000 timesRepeat: [ | c | c := OrderedCollection new: 10000. 1 to: 10000 do: [ :i | c add: i ] ] ] timeToRun 2540 [ 10000 timesRepeat: [ | c | c := OrderedCollection new: 0. 1 to: 10000 do: [ :i | c add: i ] ] ] timeToRun 2879 [ 10000 timesRepeat: [ | c | c := OrderedCollection new: 1000. 1 to: 10000 do: [ :i | c add: i ] ] ] timeToRun 2784 Apparently Squeak takes more time to allocate the large array than Pharo? That would explain why the first run is so much slower than the other 3 - the exact opposite of Max's results (for Pharo 1.3 - but inline with Pharo4 - although not as extreme as Pharo4). Then, what about an array that only adds at the beginning (instead of end)? I would expect worse performance - especially if I removed the space at the beginning. WIthout any of those changes, though: [ 10000 timesRepeat: [ | c | c := OrderedCollection new: 100000. 1 to: 10000 do: [ :i | c addFirst: i ] ] ] timeToRun 2782 [ 10000 timesRepeat: [ | c | c := OrderedCollection new: 10000. 1 to: 10000 do: [ :i | c addFirst: i ] ] ] timeToRun 1845 [ 10000 timesRepeat: [ | c | c := OrderedCollection new: 0. 1 to: 10000 do: [ :i | c addFirst: i ] ] ] timeToRun 2052 [ 10000 timesRepeat: [ | c | c := OrderedCollection new: 1000. 1 to: 10000 do: [ :i | c addFirst: i ] ] ] timeToRun 1962 Weird that it turned out faster. Maybe it has to do with the first time it runs out of room, it move data (and doesn't allocate a new array?). Stephan's code (in the same image): [ 10000 timesRepeat: [ | c | c := OrderedCollection new: 100000. c add: 1. 2 to: 10000 do: [ :i | c add: i beforeIndex: (i atRandom) ] ] ] timeToRun 200434 This last is much slower - every time it adds an value, it forces a copy of the data. It will not be as fast as the others. -cbc On Wed, Jan 14, 2015 at 6:05 AM, Stephan Eggermont <stephan@stack.nl> wrote:
I'm more worried about this part.
[ 10000 timesRepeat: [ | c | c := OrderedCollection new. c add: 1. 2 to: 10000 do: [ :i | c add: i beforeIndex: (c atRandom) ] ] ] timeToRun "5 min. 30 s."
Stephan