[racket] Stuttering problems with big-bang

From: Greg Hendershott (greghendershott at gmail.com)
Date: Wed Aug 7 20:04:55 EDT 2013

I didn't get any noticeable jitter. Noticed I had "Racket | Limit
Memory..." set to 2048 MB.

I reduced it to 64 MB. Still no jitter.

I cranked it down to 8 MB (the minimum). Then I got some jitter. Not
extreme, but noticeable.

The variance in people's reported experiences might be due (partly) to that?

On Wed, Aug 7, 2013 at 6:16 PM, Carl Eastlund <cce at ccs.neu.edu> wrote:
> For reference, I was on IRC with Jack when he first ran into this, and
> reproduced the jittery behavior on my own machine with a freshly started
> DrRacket.  The first time I ran the program, and perhaps every 10th time I
> ran it, it would hiccup briefly within a second of hitting run, then run
> smoothly.  This is on a relatively recent Mac Mini with 16 GB RAM, 4
> physical / 8 virtual cores, and little else running at the time.
> Carl Eastlund
> On Wed, Aug 7, 2013 at 5:22 PM, Robby Findler <robby at eecs.northwestern.edu>
> wrote:
>> 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).
>> Robby
>> 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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