On Thu, Dec 24, 2009 at 02:30:38AM +0100, Levente Uzonyi wrote:
> On Wed, 23 Dec 2009, David T. Lewis wrote:
> 
> >On Wed, Dec 23, 2009 at 11:07:54PM +0100, Levente Uzonyi wrote:
> >>On Wed, 23 Dec 2009, David T. Lewis wrote:
> >>>
> >>>That said, performance is poor so this is not ready for prime time.
> >>>I'm attaching an update that is somewhat less bad, but still nowhere
> >>>near good enough (3 or 4 times slower than StandardSourceFileArray).
> >>>
> >>
> >>Which part is 3-4 times slower? Can you show us your benchmark?
> >>
> >
> >I'm glad you asked. There was a typo in my test, and performance
> >seems to be pretty good after all. Here is what I was checking:
> >
> > Time millisecondsToRun: [
> >	sf := StandardSourceFileArray new.
> >	(16r1000000 to: 16r1FFFFFF by: 11) do: [:e |
> >		i := sf fileIndexFromSourcePointer: e.
> >		p := sf filePositionFromSourcePointer: e.
> >		a := sf sourcePointerFromFileIndex: i andPosition: p.
> >		a = e ifFalse: [self error: 'snafu']]
> >	] ==> 3391
> >
> > Time millisecondsToRun: [
> >	sf := ExpandedSourceFileArray new.
> >	(16r1000000 to: 16r1FFFFFF by: 11) do: [:e |
> >		i := sf fileIndexFromSourcePointer: e.
> >		p := sf filePositionFromSourcePointer: e.
> >		a := sf sourcePointerFromFileIndex: i andPosition: p.
> >		a = e ifFalse: [self error: 'snafu']]
> >	] ==> 3220
> >
> 
> My slightly modified (but semantically the same) version:
> 
> { StandardSourceFileArray. ExpandedSourceFileArray } collect: [ :class |
> 	[
> 		| sf |
> 		sf := class new.
> 		16r1000000 to: 16r1FFFFFF by: 11 do: [:e |
> 			| i p a |
> 			i := sf fileIndexFromSourcePointer: e.
> 			p := sf filePositionFromSourcePointer: e.
> 			a := sf sourcePointerFromFileIndex: i andPosition: p.
> 			a = e ifFalse: [self error: 'snafu' ] ] ] timeToRun ]
> 
> gives #(766 682) on my pc.
> 
> So I think the performance is "solved". :)

Levente, Igor,

Thank you. Apparently I accidentally concluded that there was a
performance problem, then profiled and tweaked it a bit, with the
net result that performance is very slightly improved compared to
StandardSourceFileArray. This has no practical impact whatsoever,
but I guess there are worse things that could result from a dumb
mistake :)

Dave