[racket] Stuttering problems with big-bang

From: Greg Hendershott (greghendershott at gmail.com)
Date: Wed Aug 7 20:10:26 EDT 2013

p.s. Trying again and using "View | Log", and letting it run a longer
time. At first, still just tiny jitters. Then I hit two major GCs,
each of which were obviously quite noticeable:

GC: 0:min @ 371,081K(+-44,377K)[+28,568K]; free 25,584K(-25,584K) 16ms @ 68466
GC: 0:min @ 378,376K(+-51,672K)[+28,592K]; free 29,628K(-29,628K) 13ms @ 69192
GC: 0:min @ 381,597K(+-54,893K)[+28,588K]; free 31,009K(-31,009K) 8ms @ 69930
GC: 0:min @ 383,394K(+-56,690K)[+28,588K]; free 30,956K(-30,956K) 9ms @ 70715
GC: 0:min @ 385,224K(+-58,520K)[+28,588K]; free 28,722K(-28,722K) 8ms @ 71499
GC: 0:min @ 389,286K(+-62,582K)[+28,588K]; free 30,072K(-30,072K) 8ms @ 72219
GC: 0:min @ 392,017K(+-65,313K)[+28,588K]; free 30,095K(-30,095K) 7ms @ 72938
GC: 0:min @ 394,711K(+-68,007K)[+28,588K]; free 30,044K(-30,044K) 7ms @ 73759
GC: 0:min @ 397,468K(+-70,764K)[+28,588K]; free 30,059K(-30,059K) 8ms @ 74500
GC: 0:min @ 400,196K(+-73,492K)[+28,588K]; free 30,049K(-30,049K) 7ms @ 75310
GC: 0:min @ 402,932K(+-76,228K)[+28,588K]; free 30,069K(-30,069K) 9ms @ 76058
GC: 0:MAJ @ 405,652K(+-78,948K)[+28,588K]; free 196,329K(-196,329K)
548ms @ 76883
GC: 0:MAJ @ 242,109K(+84,594K)[+28,476K]; free 47,896K(-39,144K) 491ms @ 78139
GC: 0:min @ 226,994K(+90,957K)[+28,472K]; free 29,742K(-29,742K) 10ms @ 79233
GC: 0:min @ 230,034K(+87,917K)[+28,472K]; free 31,030K(-31,030K) 6ms @ 79926
GC: 0:min @ 231,803K(+86,148K)[+28,472K]; free 29,749K(-29,749K) 8ms @ 80613
GC: 0:min @ 234,835K(+83,116K)[+28,472K]; free 31,011K(-31,011K) 8ms @ 81294

This in DrRacket. Robby's suggestion to run command-line is better
idea since it takes DrRacket itself out of the mix.

On Wed, Aug 7, 2013 at 8:04 PM, Greg Hendershott
<greghendershott at gmail.com> wrote:
> 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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