[erlang-questions] Early Out of Memory

Vance Shipley <>
Fri Mar 1 14:03:31 CET 2013


On Fri, Mar 01, 2013 at 10:33:35AM +0100, Patrik Nyblom wrote:
}  Looks like you're running a 32 bit VM, in which case you have at a
}  absolute maximum 4GB of memory. A heap allocation of 1.3 GB means
}  an old version of the heap of possibly the same size (copying GC) +
}  old heap generations and so on. A heap also needs to have
}  continuous virtual memory, so the chance of having a single process
}  with this much heap running on a 32bit VM is slim at best. If you
}  have a lot of physical memory in the machine, run a 64bit OS and a
}  64bit Erlang VM.

Patrik,

Fair enough, I didn't realize that I had forgotten to build R16B as
64 bit on my MacBook Pro.  When I did the test happily used up all
16GB of physical memory and 10GB of swap before I killed it.

But can you explain this one?:

   Erlang R16B (erts-5.10.1) [source] [64-bit halfword] [smp:8:8] [async-threads:10] [kernel-poll:false]
   
   Eshell V5.10.1  (abort with ^G)
   1> F = fun(F, Acc) -> F(F, [lists:seq(1,1000) | Acc]) end.
   #Fun<erl_eval.12.17052888>
   2> F(F, []).
   
   Crash dump was written to: erl_crash.dump
   eheap_alloc: Cannot allocate 790960704 bytes of memory (of type "old_heap").
   Aborted (core dumped)

Above I am running an R16B 64-bit halfword emulator on a server with 6GB
of physical memory.

What are the system limits with the halfword emulator?  I assume that I
can't have a binary over 4GB.  Can I have an ets table bigger than 4GB?

-- 
	-Vance


On 03/01/2013 07:09 AM, Vance Shipley wrote:
}  In the pathological example below why is eheap_alloc failing to
}  allocate 1.4GB of memory on a system with many more gigabytes of
}  memory available?
}  
}  Erlang R16B (erts-5.10.1) [source] [smp:8:8] [async-threads:10] [hipe] [kernel-poll:false]
}  
}  Eshell V5.10.1  (abort with ^G)
}  1> F = fun(F, Acc) -> F(F, [lists:seq(1,1000) | Acc]) end.
}  #Fun<erl_eval.12.17052888>
}  2> F(F, []).
}  
}  Crash dump was written to: erl_crash.dump
}  eheap_alloc: Cannot allocate 1366780092 bytes of memory (of type "heap").
}  Abort trap: 6




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