[Vm-dev] Re: [Enh][VM] primitiveApplyToFromTo for the heart of the enumeration of collections?

[Andreas Raab]

Where is the other half of the changes? What you sent isn't enough to 
generate a functioning VM. I'm in particular curious how you've dealt 
with the loop inlining and it seems there is some code missing which 
does that.

Cheers,
    - Andreas

Klaus D. Witzel wrote:
> Attached is #primitiveApplyToFromTo as it compiles and runs using the 
> win32 Squeak 3.7.1 build environment here; I'm testing it with the 3.8 
> and 3.9 images.
> 
> The performance is compared against plain #do: (apples v.s. apples) and 
> #to:do: (apples v.s. oranges) further down below.
> 
> Compared to #do: with block, #applyTo:from:to: with block is 
> definitively faster (smaller hidden constants) and there also is at 
> least one item waiting for optimization (and for me having time to do 
> that).
> 
> I'd say that the factor can arrive at about 2 (#do: v.s. 
> #applyTo:from:to:). But the primitive will not outperform an inlined 
> #to:do: this was clear from the beginning. As Jon wrote, the primitive 
> is good for "fixing" the standard enumeration methods so they all have 
> (more or less) identical performance.
> 
> The current implementation is for non-Strings only (as dictated by an 
> atCache parameter) but can of course be extended to work with Strings. 
> Another item that's missing is returning self from the primitive, this 
> is currently handled by falling into the shadow which then returns (and 
> some superflous bytecode cycles are burned).
> 
> Example method in SequenceableCollection
> applyTo: aBlock from: index to: limit
>     <primitive: 164>
>     [index <= limit] whileTrue:
>         [aBlock value: (self basicAt: index).
>          thisContext tempAt: 2 put: index + 1]
> 
> The shadow code is exactly what is done by the primitive. As discussed 
> ealier,the primitive can be called from #commonSend and from 
> #commonReturn and in both cases might decide to exit with primitiveFail.
> 
> The overrides for #commonSend and #commonReturn are not attached but if 
> you want them ask me.
> 
> Any questions?
> 
> /Klaus
> 
> --------------------
> 
> | time array sum |
>     array := (1 to: 10565520) collect: [:none | 1].
>     Smalltalk garbageCollect.
>     time := Time millisecondsToRun: [
>         sum := array sum].
>     sum.
>     time
> => 9093
> 
> --------------------
> 
> | time array sum |
>     array := (1 to: 10565520) collect: [:none | 1].
>     Smalltalk garbageCollect.
>     time := Time millisecondsToRun: [
>         sum := 0.
>         array do: [:each | sum := sum + each]].
>     sum.
>     time
> => 4764
> 
> --------------------
> 
> | time array sum |
>     array := (1 to: 10565520) collect: [:none | 1].
>     Smalltalk garbageCollect.
>     time := Time millisecondsToRun: [
>         sum := 0.
>         array applyTo: [:each | sum := sum + each]
>             from: 1 to: array size].
>     sum.
>     time
> => 3499
> 
> --------------------
> 
> | time array sum |
>     array := (1 to: 10565520) collect: [:none | 1].
>     Smalltalk garbageCollect.
>     time := Time millisecondsToRun: [
>         sum := 0.
>         1 to: array size do: [:index | sum := sum + (array at: index)]].
>     sum.
>     time
> => 2089
> 
> --------------------
> 
> 
> ------------------------------------------------------------------------
> 
>