[racket] Stuttering problems with big-bang

From: Robby Findler (robby at eecs.northwestern.edu)
Date: Wed Aug 7 17:22:20 EDT 2013

I just tried this on my mac (a fairly recent machine but not a super-duper
powerhouse) and it didn't seem jittery.

What happens if you save it in "file.rkt" and, from a terminal window, run
"racket file.rkt"? Here's the precise command I ran (on a mac):

    /Applications/Racket\ v5.3.5/bin/racket -W debug at GC  ~/file.rkt

I didn't see too many GCs once the game started and the ones I saw were
unlikely to be noticeable (they were 3-5 msec; well below the 16 msec
screen refresh rate).

If that makes a difference on your machine, perhaps that means it is time
to restart DrRacket (as GCs can take significantly longer for programs
running inside DrRacket, esp. if there is a leak somewhere).


On Wed, Aug 7, 2013 at 2:58 AM, Robby Findler
<robby at eecs.northwestern.edu>wrote:

> Well, allocation is what triggers GC and there appears to be a fair amount
> of that in your program. I am not in a good position to run your code and
> nothing jumps out at me from a first glance at the gist but probably it is
> allocation that originates there (not that that
> means your code is necc. buggy).
> Fundamentally, functional image construction (and lists) requires
> allocation and allocation requires GC. That said there is probably
> something's we can fix here. I will try to take a closer look in the coming
> days of no one beats me to it.
> Robby
> On Wednesday, August 7, 2013, Jack Firth wrote:
>> Hey users, I'm experimenting with some simple games using big-bang from
>> 2htdp/universe and I keep running into stuttering problems. It seems to be
>> the garbage collector slowing things down (green recycle symbol in drracket
>> is on whenever the program is frozen).
>> Increasing the memory limit or removing the limit altogether doesn't seem
>> to affect the problem, and I've checked in the IRC and it occurs on other
>> machines as well, all of which have the specs that it shouldn't have any
>> problems with slowdown. Are there issues with big-bang and it's event
>> handling?
>> Source - https://gist.github.com/Universalist235/6171371
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