Re: [Caml-list] Potential OCaml-ZMQ memory management problems

[Anders Fugmann <anders@fugmann.net>]

The garbage collector settings seems quite sane to me. You could try to 
force a major collection every call to iltrans.

Gc.major ()

It could be that the segfault is really an out of memory situation. 
Maybe you have a leak in your code somewhere (Not releasing references 
to large objects).

/Anders


On 12/04/2014 09:02 AM, Kenneth Adam Miller wrote:
> I'm using zmq and ocaml-zmq as installed by opam; I'm not at my work
> computer or I would provide those details.
>
> Yes, I will try to work on creating a reproducible script
>
> Could it possibly be a call to Tunegc.set_gc () from
> https://github.com/argp/bap/blob/master/ocaml/tunegc.ml ?
>
> I notice that this error didn't appear in single calls to my utility;
> basically, I'm using iltrans from bap and I'm using it in a long living
> process, unlike the current implementation which expects a few
> transformations and then process death. I did notice that when I run it,
> if I'm watching system monitor that it begins consuming vast amounts of
> memory (quickly grows from a few megabytes to 800+) before it hits
> segfault. Would there be any way to restore the aggressiveness of the GC
> between calls to iltrans?
>
> On Thu, Dec 4, 2014 at 2:55 AM, Anders Fugmann <anders@fugmann.net
> <mailto:anders@fugmann.net>> wrote:
>
>     Hi Kenneth,
>
>     The Ocaml-zmq code copies data from received messages into memory under
>     the control of the ocaml garbage collector, and immediatly frees the
>     ZMQ buffers.
>
>     You do not need to explicitly free the data received from call to recv.
>
>     Can you produce a small sample code that exposes the problem? We are
>     using the ocaml-zmq binding extensively, and have not seen any problems.
>
>     If I were to take a wild guess, it either a mismatch between library
>     versions or the garbage-collector collecting the socket or zmq context.
>
>     What version of the ocaml-zmq bindings and libzmq (c impl) are you
>     using?
>
>     /Anders
>
>
>
>     On 12/04/2014 07:09 AM, Kenneth Adam Miller wrote:
>
>         I'm using ocaml-zmq (https://github.com/issuu/__ocaml-zmq
>         <https://github.com/issuu/ocaml-zmq>) and I think I'm
>         encountering a memory management issue. I could be wrong
>         however, but
>         basically the issue (I think) is I have a rather large set of
>         messages
>         to send via zmq, and I'm getting a segfault.
>
>         Does anybody know if I need to free the strings received from
>         zmq recv
>         functions in ocaml? If so how do I do that from ocaml?
>
>         There's no code because this is just a general novice ocaml
>         questions.
>
>
>