[Spread-users] Memory leak? FD leak? Other?

Jonathan Stanton jonathan at cnds.jhu.edu
Fri Aug 20 18:16:59 EDT 2004

Yes. John is right. But the fd thing is a bug which is why I wanted to 
distinguish between the two cases. 

Because Spread internally caches a lot of memory, and that even when we 
call free, the OS reported memory usage will often not go down it is hard 
to see when Spread really has a leak and when it doesn't. Spread is 
designed to be somewhat memory aggressive (in order to increase speed in 
the common case of a stable workload of messages) but David is trying to 
trigger cases that he thinks should release the memory (and I agree at 
some point the memory does have to be returned and shouldn't crash/swap 
out the system). 

I'll try out David's stress program and see what kind of memory load we 
are getting.



On Fri, Aug 20, 2004 at 01:03:09PM -0400, John Schultz wrote:
> David Shaw wrote:
> >I believe I have triggered both.  No memory is released by the daemon,
> >and some fds are left behind when using the sabuse program I sent.
> >
> >Currently, the sabuse program connects to spread and justs calls
> >SP_multicast over and over again.  If you modify the program to
> >SP_connect, send 500 messages, then SP_disconnect and then repeat the
> >whole connect-send-disconnect cycle over and over, you get different
> >behavior when killing sabuse: there are no fds left open in spread,
> >but the memory is still not returned.
> >
> >David
> >
> Jonathan, doesn't Spread's memory subsystem keep memory it has allocated 
> around?  Furthermore, even if it releases that memory don't most 
> processes never release allocated memory pages back to the operating 
> system until they finish?  So if any process has a large spike in memory 
> usage, then their memory footprint as far as the OS is concerned never 
> shrinks?
> -- 
> John Lane Schultz
> Spread Concepts LLC
> Phn: 443 838 2200
> _______________________________________________
> Spread-users mailing list
> Spread-users at lists.spread.org
> http://lists.spread.org/mailman/listinfo/spread-users

Jonathan R. Stanton         jonathan at cs.jhu.edu
Dept. of Computer Science   
Johns Hopkins University    

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