Erlang code is only memory referenced once for each module. <div><br></div><div>Constants in a module (literals) will be garbage collected to the heap upon a purge if it is reachable. Hence memory can increase upon a purge and reload.</div>
<div><br></div><div><div>Module loading is done from a single thread. The VM will block all other threads, loads the module code and then pushes references to export entries. Upon completion the threads are released.</div>
<div><br></div><div>// Björn-Egil</div><div><br><br><div class="gmail_quote">2011/11/21 Max Bourinov <span dir="ltr"><<a href="mailto:bourinov@gmail.com">bourinov@gmail.com</a>></span><br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
I tend to think that Ladislav Lenart is right... At least I don't see any reason why actual code should be loaded more that once.<div><br></div><div>Waiting for Erlang Super Master to clarify....</div><div><br><div><div>
Best regards,</div><div>Max</div><div><div class="h5"><br><br>
<br><br><div class="gmail_quote">2011/11/21 Max Bourinov <span dir="ltr"><<a href="mailto:bourinov@gmail.com" target="_blank">bourinov@gmail.com</a>></span><br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Does anybody knows how it exactly runs?<div><div><div><br><div><div>Best regards,</div><div>Max</div><br><br>
<br><br><div class="gmail_quote">2011/11/21 CGS <span dir="ltr"><<a href="mailto:cgsmcmlxxv@gmail.com" target="_blank">cgsmcmlxxv@gmail.com</a>></span><br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<u></u>
<div text="#000000" bgcolor="#ffffff">
Sorry for not being explicit. I was referring not only to the data,
but also to the code itself. As far as I noticed, Erlang does not
make any difference between loading the same module in different
processes and different modules in different processes. Each process
instance is independent and does not share any bit of its memory
with other instances (it can copy, but does not share). I might be
wrong in my observation, though (only a developer can be 100% sure).<br>
<br>
My test consisted in starting the same piece of code in two
different Erlang sessions (processes as you call them) and I noticed
the same memory consumption for each (top -d 1 -p <PID of the
system process where your code is loaded>). You can test that as
well and compare it with the beam size. As I said, I might be wrong
because my code has a certain level of granularity which doesn't
allow very large functions (I avoid large functions for better
monitoring the states).<br>
<br>
I hope this answer will at least help you to convince yourself about
which answer is correct.<span><font color="#888888"><br>
<br>
CGS</font></span><div><div><br>
<br>
<br>
<br>
<br>
<br>
On 11/21/2011 12:51 PM, Max Bourinov wrote:
<blockquote type="cite">About the process data it is absolutely clean how
Erlang handles it. I just want some clarification about the code.
<div><br>
</div>
<div><br clear="all">
<div>Best regards,</div>
<div>Max</div>
<br>
<br>
<br>
<br>
<div class="gmail_quote">2011/11/21 CGS <span dir="ltr"><<a href="mailto:cgsmcmlxxv@gmail.com" target="_blank">cgsmcmlxxv@gmail.com</a>></span><br>
<blockquote class="gmail_quote" style="margin:0pt 0pt 0pt 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
<div text="#000000" bgcolor="#ffffff"> One instance per
process, one memory allocation per process (even if it is
the same code running). Erlang has no explicit knowledge
of beam shared objects as far as I know. If somebody knows
differently, please, correct me.<span><font color="#888888"><br>
<br>
CGS</font></span>
<div>
<div><br>
<br>
<br>
<br>
<br>
On 11/21/2011 12:40 PM, Max Bourinov wrote:
<blockquote type="cite">
<div>Thank you for your reply! But in Erlang
processes, not threads. There are some differences
between them...</div>
<div><br>
</div>
<div><br>
<br>
Отправлено с iPhone</div>
<div><br>
21.11.2011, в 15:05, CGS <<a href="mailto:cgsmcmlxxv@gmail.com" target="_blank">cgsmcmlxxv@gmail.com</a>>
написал(а):<br>
<br>
</div>
<blockquote type="cite">
<div> Hi, Max,<br>
<br>
Not an expert, but I think the memory is
multiplied by the number of threads. Meaning,
you start with an initial heap for that thread
and add to that the states and other internal
variables (repeat that for all the threads). At
least that I noticed from my codes by now. If I
am wrong, I apologize.<br>
<br>
Cheers,<br>
CGS<br>
<br>
<br>
<br>
<br>
On 11/21/2011 11:57 AM, Max Bourinov wrote:
<blockquote type="cite">Hi Erlangers,
<div><br>
</div>
<div>I am wondering how my Erlang app would
behave in this case:</div>
<div><br>
</div>
<div>I have a lot identical processes (the
same module, state of couse is different in
each process). The module that I swap many
times has a huge function. I want to clarify
how much memory it will take? It will take
memory for that huge function in each
process or only once?</div>
<div><br>
</div>
<div>I believe it will take memory only once,
but I want to make sure.</div>
<div><br clear="all">
<div>Best regards,</div>
<div>Max</div>
<br>
<br>
</div>
<pre><fieldset></fieldset>
_______________________________________________
erlang-questions mailing list
<a href="mailto:erlang-questions@erlang.org" target="_blank">erlang-questions@erlang.org</a>
<a href="http://erlang.org/mailman/listinfo/erlang-questions" target="_blank">http://erlang.org/mailman/listinfo/erlang-questions</a>
</pre>
</blockquote>
<br>
</div>
</blockquote>
<blockquote type="cite">
<div><span>_______________________________________________</span><br>
<span>erlang-questions mailing list</span><br>
<span><a href="mailto:erlang-questions@erlang.org" target="_blank">erlang-questions@erlang.org</a></span><br>
<span><a href="http://erlang.org/mailman/listinfo/erlang-questions" target="_blank">http://erlang.org/mailman/listinfo/erlang-questions</a></span><br>
</div>
</blockquote>
</blockquote>
<br>
</div>
</div>
</div>
</blockquote>
</div>
<br>
</div>
</blockquote>
<br>
</div></div></div>
</blockquote></div><br></div></div>
</div></div></blockquote></div><br></div></div></div></div>
<br>_______________________________________________<br>
erlang-questions mailing list<br>
<a href="mailto:erlang-questions@erlang.org">erlang-questions@erlang.org</a><br>
<a href="http://erlang.org/mailman/listinfo/erlang-questions" target="_blank">http://erlang.org/mailman/listinfo/erlang-questions</a><br>
<br></blockquote></div><br></div></div>