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<div class="moz-cite-prefix">If garbage collection isn't happening
quick enough, you can generate the problematic data within a
temporary process to make the temporary process' death trigger
garbage collection naturally. Doing that is a natural way to
approach it. The tuning is something additional that is
optional. I have a module I had used in the past to be as harsh
as possible to the garbage collector (i.e., force it as much as
possible) here
<a class="moz-txt-link-freetext" href="https://gist.github.com/okeuday/dee991d580eeb00cd02c">https://gist.github.com/okeuday/dee991d580eeb00cd02c</a> but I don't
think it is necessary with a decent architecture in-place (being
that harsh shouldn't be necessary). If you need to check the
memory consumption of your processes
<a class="moz-txt-link-freetext" href="http://www.erlang.org/doc/man/instrument.html">http://www.erlang.org/doc/man/instrument.html</a> is very helpful.<br>
<br>
On 09/22/2014 07:24 PM, Eranga Udesh wrote:<br>
</div>
<blockquote
cite="mid:CALg+e6yA6LopXvpEwxgzSzz8gBR78dfrrr89g3ju17vh0pgEqw@mail.gmail.com"
type="cite">
<div dir="ltr">Thanks for the information received so far.
<div><br>
</div>
<div>Wouldn't it be good for Erlang to have a single object
garbage collection function/bif? For example, when I no longer
require a large object, I force to garbage collect it, without
making a full sweep?</div>
<div><br>
</div>
<div>As mentioned in the document, a full sweep may degrade the
performance.</div>
<div><br>
</div>
<div>- Eranga</div>
</div>
<div class="gmail_extra"><br>
<div class="gmail_quote">On Tue, Sep 23, 2014 at 12:10 AM,
Björn-Egil Dahlberg <span dir="ltr"><<a
moz-do-not-send="true"
href="mailto:wallentin.dahlberg@gmail.com" target="_blank">wallentin.dahlberg@gmail.com</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">
<div dir="ltr">It should suffice by running an
erlang:garbage_collect/0 directly after extracting some
parts of the structure:
<div><br>
</div>
<div>
<div style="font-family:arial,sans-serif;font-size:13px">
<div>function1() -></div>
<div>
<blockquote style="margin:0px 0px 0px
40px;border:none;padding:0px">X1 = ... fetch a
large object ....</blockquote>
<blockquote style="margin:0px 0px 0px
40px;border:none;padding:0px">... some
processing...</blockquote>
<blockquote style="margin:0px 0px 0px
40px;border:none;padding:0px">X2 = ... extract a
part of X1 ...<br>
erlang:garbage_collect(),<br>
... long running job....<br>
</blockquote>
</div>
<div><br>
</div>
<div>As long as the object of X1 is not referenced by
the process after the explicit call to the gc,
you're fine.</div>
<div>Note also, an explicit call to garbage_collect/0
will always to a 'fullsweep'.</div>
<div><br>
</div>
<div>Ofc, as Jesper mentioned, the it's probably
preferable not to fetch the whole object if
possible.</div>
<span class="HOEnZb"><font color="#888888">
<div><br>
</div>
<div>// Björn-Egil</div>
<div><br>
</div>
</font></span></div>
</div>
</div>
<div class="HOEnZb">
<div class="h5">
<div class="gmail_extra"><br>
<div class="gmail_quote">2014-09-22 19:56 GMT+02:00
Jesper Louis Andersen <span dir="ltr"><<a
moz-do-not-send="true"
href="mailto:jesper.louis.andersen@gmail.com"
target="_blank">jesper.louis.andersen@gmail.com</a>></span>:<br>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">
<div dir="ltr">In general: No it won't. GC will
trigger once the process has allocated enough
data. If your processing is allocating enough
data, this will quickly happen and you don't
have to worry. If not, you may have to gently
persuade the process to do so. There are several
ways:
<div><br>
</div>
<div>* Set fullsweep_after on the process with a
low value (0) and run erlang:garbage_collect()</div>
<div>* Go through a hibernation with an
immediate wakeup (feels ugly to me)</div>
<div>* Handle fetching and extraction in a
separate process and send the extracted part
'x' back as a message. This will free up
memory almost immediately for other processes
to use (simple and elegant)</div>
<div>* Don't fetch the large object in the first
place, but make it possible to ask for an
extraction only. Or stream data a bit at a
time and handle the stream in chunks rather
than everything at once.</div>
<div><br>
</div>
</div>
<div class="gmail_extra"><br>
<div class="gmail_quote">
<div>
<div>On Mon, Sep 22, 2014 at 4:11 PM, Eranga
Udesh <span dir="ltr"><<a
moz-do-not-send="true"
href="mailto:eranga.erl@gmail.com"
target="_blank">eranga.erl@gmail.com</a>></span>
wrote:<br>
</div>
</div>
<blockquote class="gmail_quote"
style="margin:0 0 0 .8ex;border-left:1px
#ccc solid;padding-left:1ex">
<div>
<div>
<div dir="ltr">Hi,
<div><br>
</div>
<div>I'm trying to optimize my memory
consumption in Erlang VM and to
garbage collect as soon as possible.</div>
<div><br>
</div>
<div>Let's say I have a large object,
"X", After some processing, I only
need to work on small part of X,
called "x".</div>
<div><br>
</div>
<div>Can someone advice me if below
process flow will put the large
object X in to garbage collection,
while waiting for the long running
job to continue?</div>
<div><br>
</div>
<div>
<div>function1() -></div>
<div>
<blockquote style="margin:0px 0px
0px
40px;border:none;padding:0px">X
= ... fetch a large object....</blockquote>
<blockquote style="margin:0px 0px
0px
40px;border:none;padding:0px">...
some processing...</blockquote>
<blockquote style="margin:0px 0px
0px
40px;border:none;padding:0px">x
= ... extract a part of X...<br>
... long running job....<br>
</blockquote>
</div>
</div>
<div><br>
</div>
<div>If it's not putting X into
garbage collection, does below
change do that?</div>
<div><br>
</div>
<div>function1() -></div>
<div>
<blockquote style="margin:0px 0px
0px 40px;border:none;padding:0px">
<div>X = ... fetch a large
object....</div>
</blockquote>
<blockquote style="margin:0px 0px
0px 40px;border:none;padding:0px">
<div>... some processing...</div>
</blockquote>
<blockquote style="margin:0px 0px
0px 40px;border:none;padding:0px">x
= ... extract a part of X...<br>
function2(x).<br>
<br>
</blockquote>
function2(x) -></div>
<div>
<blockquote style="margin:0px 0px
0px 40px;border:none;padding:0px">
<div>... long running job...</div>
</blockquote>
<br>
</div>
<div>Tks,</div>
<div>- Eranga</div>
</div>
<br>
</div>
</div>
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</blockquote>
</div>
<span><font color="#888888"><br>
<br clear="all">
<div><br>
</div>
-- <br>
J.
</font></span></div>
<br>
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