[racket] big-bang is slow to render on screen?

Here's my log after pasting the source into command-line racket 6.0, Ubuntu
12.04 32-bit:

to-draw at 1649
to-draw: cpu time: 0 real time: 2 gc time: 0
on-key a at 2934
to-draw at 2934
to-draw: cpu time: 0 real time: 2 gc time: 0
on-key s at 2970
to-draw at 2970
to-draw: cpu time: 4 real time: 3 gc time: 0
on-key d at 3044
on-key f at 3044
to-draw at 3045
to-draw: cpu time: 0 real time: 0 gc time: 0
to-draw at 3069
to-draw: cpu time: 0 real time: 1 gc time: 0
on-key a at 3198
on-key s at 3198
to-draw at 3199
to-draw: cpu time: 4 real time: 3 gc time: 0
to-draw at 3329
to-draw: cpu time: 4 real time: 1 gc time: 0
to-draw at 3392
to-draw: cpu time: 0 real time: 1 gc time: 0
on-key g at 3430
on-key j at 3430
on-key k at 3430
to-draw at 3430
to-draw: cpu time: 4 real time: 1 gc time: 0
to-draw at 3467
to-draw: cpu time: 0 real time: 1 gc time: 0
on-key a at 3504
on-key l at 3504
to-draw at 3505
to-draw: cpu time: 0 real time: 1 gc time: 0
to-draw at 3547
to-draw: cpu time: 4 real time: 1 gc time: 0
to-draw at 3572
to-draw: cpu time: 0 real time: 1 gc time: 0
on-key h at 3602
to-draw at 3602
to-draw: cpu time: 0 real time: 1 gc time: 0
on-key k at 3659
on-key ; at 3659
to-draw at 3659
to-draw: cpu time: 4 real time: 3 gc time: 0
to-draw at 3689
to-draw: cpu time: 0 real time: 1 gc time: 0
to-draw at 3725
to-draw: cpu time: 0 real time: 1 gc time: 0
to-draw at 3776
to-draw: cpu time: 0 real time: 1 gc time: 0



On Mon, Apr 21, 2014 at 10:00 AM, Laurent <laurent.orseau at gmail.com> wrote:

> I have a 2htdp/universe program that used to run fast enough a few months
> ago, but now it is very slow and not usable.
> The slowness seems to be because of the on-screen rendering, and not
> because of the generation of the image.
>
> Here is a stripped-down version that shows this behavior:
> https://gist.github.com/Metaxal/11142941
>
> In the following log, you see that the `on-key` events are very close one
> to the other (in milliseconds after the beginning of the program), but the
> corresponding `to-draw` events are separated by more than a second, even
> though generating the image (cpu time) takes almost no time:
>
> on-key a at 6906
> on-key u at 6912
> on-key i at 6912
> on-key e at 6913
> to-draw at 6913
> to-draw: cpu time: 4 real time: 3 gc time: 0
> to-draw at 8598
> to-draw: cpu time: 4 real time: 2 gc time: 0
> to-draw at 11948
> to-draw: cpu time: 4 real time: 2 gc time: 0
> to-draw at 13631
> to-draw: cpu time: 0 real time: 2 gc time: 0
> to-draw at 161839
> to-draw: cpu time: 4 real time: 9 gc time: 0
>
> During those long seconds, Xorg is almost at 100% cpu.
>
> However, using an empty scene instead of an image is fast.
> The time also depends on the size of the grid.
>
> I'm using Ubuntu 12.04 64bits.
> I have tried to replicate the behavior on older versions of racket (5.3.1
> and 5.90.0.9) but it's the same. So maybe the problem is not on Racket's
> side but something has changed in Ubuntu?
>
> Does anyone else see the same behavior, either on the same platform or on
> a different one?
>
> Thanks,
> Laurent
>
>
> ____________________
>   Racket Users list:
>   http://lists.racket-lang.org/users
>
>
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