[Vm-dev] Re: A trick to speedup #become: (but not becomeForward:)

[Andreas Raab]

On 7/31/2011 6:56, Igor Stasenko wrote:
> And it works! All become tests are green.
> See attached for VM and image side code.

Good idea. But your benchmark is a little off:

> Now most interesting thing. How much speed we gain?
>
> Before:
>
> | x y |
>
> x := 'ab' copy.
> y := 'cd' copy.
>
> [ 100 timesRepeat: [ x become: y ] ] timeToRun

x and y should be young in the above and the performance of #become 
should be much faster than when they are old. To wit:

[ 100 timesRepeat: [ 'ab' copy become: 'cd' copy ] ] timeToRun
=> 36

| x y |
x := 'ab' copy.
y := 'cd' copy.
Smalltalk garbageCollect. "make x and y old"
[ 100 timesRepeat: [ x become: y ] ] timeToRun
=>  1248

So I'm not sure how valid your benchmark really is.

Cheers,
   - Andreas