From: "Ara.T.Howard" <Ara.T.Howard@...>
Date: 2005-04-28T01:16:23+09:00
Subject: Re: memory leak

On Thu, 28 Apr 2005, Joe Van Dyk wrote:

> On 4/26/05, Joe Van Dyk <joevandyk@gmail.com> wrote:
>> eek.  copy/paste borked.
>>
>> See below for correct version.
>
> FYI, you'll need SysVIPC installed
> (http://deisui.org/~ueno/ruby/sysvipc.html).
>
> In essence, the code below starts a thread that uses a object to read
> from a message queue repeatedly.  If there's no messages left on the
> message queue, the #recv method throws an exception, we catch that and
> exit the loop.  The reader thread then sleeps for a second and reads
> more messages from the queue.
>
> The problem doesn't seem to be with the sending of the message over
> the message queue, rather its the receive.  Somewhere, something isn't
> being thrown away.  I used ObjectSpace to monitor the number of
> objects that existed.  The total number of Objects in memory seem to
> fluctuate, but don't increase over time (while memory is increasing).
>
> I looked at the C code for the SysVIPC module but couldn't see any
> obvious errors.
>
> Any thoughts?

can you run it under electric fence?

>
> Joe
>
>> On 4/26/05, Joe Van Dyk <joevandyk@gmail.com> wrote:
>>> Got a memory leak in the following code.. not sure if DRb is necessary
>>> in it or not.
>>>
>>> Put the code into a file named test.rb, btw.
>>>
>>> I think I tracked it down to the SystemVIPC::MessageQueue#recv method.
>>>  If I don't give it a high receive length (like 8192), I don't see the
>>> leak.  If I do give it a high length, the program takes up a very
>>> large amount of space pretty quickly... about an increase of a meg
>>> every five seconds.
>>>
>>> Any ideas?  (On my linux system, kernel.msgmax is set to 10000 if it matters)
>>>
>>
>> # test.rb
>>
>> require 'drb'
>> require 'sysvipc'
>>
>> class Foo
>>   def initialize
>>     @key = SystemVIPC::ftok("test.rb", 1)
>>     @msg = SystemVIPC::MessageQueue.new(@key, 0777 | SystemVIPC::IPC_CREAT)
>>   end
>>
>>   def recv
>>     continue = true
>>     while continue
>>       begin
>>         @msg.recv(1, 8192, SystemVIPC::IPC_NOWAIT)
>>       rescue
>>         continue = false
>>       end
>>     end
>>   end
>>
>>   def send
>>     @msg.send(1, "HELLO WORLD HELLO WORLD")
>>   end
>> end
>>
>> f = Foo.new
>> some_thread = Thread.new(f) do |foo|
>>   loop do
>>     foo.recv
>>     sleep 1
>>   end
>> end
>> some_thread = Thread.new(f) do |foo|
>>   loop do
>>     foo.send
>>     sleep 1
>>   end
>> end
>>
>> DRb.start_service('druby://localhost:8000', f)
>> DRb.thread.join
>>
>
>

-a
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