[racket] garbage collection and process idling

On Sat, Oct 16, 2010 at 9:32 PM, Greg Hendershott
<greghendershott at gmail.com> wrote:
> I thought I saw a thread devoted to calling collect-garbage
> periodically, when I browsed the web-server code before ... but I
> can't seem to find it again now.

The command line version used to do that... I think. I routinely
create such a thread when I deploy the Web server.

(thread (lambda () (let loop () (collect-garbage) (sleep X) (loop))))

for some X.

Jay

>
>> Eventually, we should improve the collector (or replace it with a
>> better one) to support incremental collection.
>
> My recent (albeit limited) experience suggests this would be very
> helpful. There are applications where it would be preferable to take
> more frequent, shorter, and more-similar-duration hits. Even if there
> were a trade-off that the total GC time were somewhat higher.
>
> Instead of
>
> ...x...x.....x............xxxxx...xxxxxxxxx.................x...x.....x...x....x...x
>
> More like
>
> ...x...x....xx....x...x...x....xx...xx....x...x......x...x...x...x.....x....x..x...x.x
>
> (I didn't carefully count the Xs, but pretend both have the same, or
> actually the latter has slightly more. And notice I'm NOT proposing
> the latter Xs are exactly evenly spaced. Just much more evenly.)
>
> In other words optimize for consistency and predictability, not solely
> for speed. Ideally allow that optimization balance to be chosen at
> runtime: How lumpy would you like your GCd potatoes.
>
> On Sat, Oct 16, 2010 at 9:24 PM, Matthew Flatt <mflatt at cs.utah.edu> wrote:
>> At Sat, 16 Oct 2010 13:40:43 -0400, Neil Van Dyke wrote:
>>> Any thoughts on how, by default, timing of garbage collection cycles is
>>> affected by whether the process is "idle".
>>>
>>> For example, if non-GC threads are all waiting on events, might the
>>> thread with GC be more likely to trigger a GC at that idle time, rather
>>> than when some threads are working?
>>
>> No.
>>
>> Eventually, we should improve the collector (or replace it with a
>> better one) to support incremental collection. Then, it would be easy
>> to use idle CPUs for GC work. Currently, though, if a GC is started,
>> then the GC has to complete before anything else can happen, so a GC is
>> triggered only by memory demand or explicit request.
>>
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-- 
Jay McCarthy <jay at cs.byu.edu>
Assistant Professor / Brigham Young University
http://teammccarthy.org/jay

"The glory of God is Intelligence" - D&C 93