Loops in Smalltalk
kennethjohnsen at mail.dk
Sun Jun 27 16:49:23 UTC 2004
I read an article about the new version of Dataflex, where it said that
the time it took to do 5000 get/set operations had been reduced from 58
to 3 seconds.
I read it like: set and get an instance variable on an object 5000
times, but I presume that something more advanced is going on
(otherwise, it's not that impressive).
But this got me wondering: how long does it take in Smalltalk?
So, I made a small class, with one instance variable: instancevar, and
three methods: instancevar, instancevar: and runTest. The two former
just gets/sets instancevar, and runTest does:
| anInt |
do: [:z |
self instancevar: z.
anInt := self instancevar.
Transcript show: anInt printString;
Now, I didn't have the "Transcript show" in it the first time I ran it.
Squeak printed: 1
Dolphin printed: 1
Question 1: Very nice. But am I missing something, where the compiler
figures out that my instancevar is not used for anything else, and
Next, I put the "Transcript show" in (I know, I know, that's not exactly
testing the loop itself).
Squeak printed: 125585
Dolphin printed: 20711
Presumably Dolphin is faster because it is targeted at Windows.
Question 2: After "5000" was printed, both systems took a couple of
seconds to come alive again (i.e. in Squeak, everything froze, in
Dolphin, I got an hourglass). What were they doing? Was that the garbage
collector at work, or?
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