Hi Andreas,

the reason will be in the gradient background of windows. The
background is processed during every update now but the previous
versions were more optimized.
I have tried this test on Squeak 3.9 with Skylark theme
(http://www.comtalk.net/Squeak/87) and it was without this slowdown
and about two times faster (without TTF).

-- Pavel

On 10/21/06, Andreas Raab <andreas.raab at gmx.de> wrote:
> Hi Guys -
>
> I noticed that briefly yesterday but did some more investigation today
> and it turns out that the tools in 3.9 have become *really* slow. And
> it's not just because of the TTF caching. I turned off TTFs completely
> and noticed that things were still slow and then I devised a little
> benchmark:
>
>    win := Browser openBrowser topView.
>    win extent: 600 at 350.
>    br := win model.
>    br systemCategoryListIndex: 1.
>    World doOneCycle.
>    Transcript cr; show: [1 to: 10 do:[:i|
>         br classListIndex: i.
>         World doOneCycle.
>    ]] timeToRun.
>
> The interesting thing about this benchmark is that you can run it
> multiple times to "increase the load" by having more browsers on the
> screen. I only noticed this accidentally but it turns out to be the
> relevant part.
>
> In 3.8 the above results in a sequence of
>         Run 1: 598 msecs
>         Run 2: 630 msecs
>         Run 3: 683 msecs
>         Run 4: 689 msecs
> So there is a little bit of slowdown when you add more browsers which is
> what I would expect (due to rounded corners triggering some extra
> overdraw, the additional structure etc).
>
> In 3.9 however, we get the following:
>         Run 1:  883 msecs
>         Run 2: 1311 msecs
>         Run 3: 1632 msecs
>         Run 4: 2006 msecs
> After four runs, we need 2.5 times as long as the first run. Something
> is causing a tremendous overhead for any additional browser on the
> screen. This matches my experience though originally I had attributed
> that to the TTF problems but it seems the issue is way deeper than that.
> Any ideas what was changed in 3.9 that could cause that slowdown?
>
> Cheers,
>    - Andreas
>
>