Out_of_memory

Out_of_memory

[Christopher Alexander Stein]

Hi, I am getting an exception Out_of_memory. The manual tells me
this is raised by the garbage collector when there is
insufficient memory to complete the computation. Is there any way
to find out what is causing this; what is gobbling up memory too
fast for the GC? Perhaps there is a way to get and analyze a core
file or a way to catch the exception and dump the heap and
garbage collector state. Any suggestions? I am using a C library,
but carefully followed the rules of;
http://caml.inria.fr/ocaml/htmlman/manual032.html
Though I suspect the C library is responsible.

Thanks

Lex

Re: [Caml-list] Out_of_memory

[Damien Doligez]

On 17 déc. 2004, at 07:44, Christopher Alexander Stein wrote:

> Hi, I am getting an exception Out_of_memory. The manual tells me
> this is raised by the garbage collector when there is
> insufficient memory to complete the computation. Is there any way
> to find out what is causing this; what is gobbling up memory too
> fast for the GC? Perhaps there is a way to get and analyze a core
> file or a way to catch the exception and dump the heap and
> garbage collector state. Any suggestions?

Have you tried using the debugger?

-- Damien

Re: [Caml-list] Out_of_memory

[Christopher Alexander Stein]

Do you mean something more than gdb? I've used gdb and I get the
following stack trace:

Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread 1075667072 (LWP 9819)]
0x0805a026 in caml_oldify_mopup ()
(gdb) bt
#0  0x0805a026 in caml_oldify_mopup ()
#1  0x0805a0e5 in caml_empty_minor_heap ()
#2  0x0805a190 in caml_minor_collection ()
#3  0x0805a21a in caml_check_urgent_gc ()
#4  0x0805ac3f in caml_alloc_string ()
#5  0x0805e138 in caml_create_string ()
#6  0x080688de in caml_interprete ()
#7  0x08059be9 in caml_main ()
#8  0x08059d60 in main ()
(gdb)

I'm not sure where to go from here. What do you recommend?

Thanks

Lex

On Sat, 18 Dec 2004, Damien Doligez wrote:

> On 17 déc. 2004, at 07:44, Christopher Alexander Stein wrote:
>
> > Hi, I am getting an exception Out_of_memory. The manual tells me
> > this is raised by the garbage collector when there is
> > insufficient memory to complete the computation. Is there any way
> > to find out what is causing this; what is gobbling up memory too
> > fast for the GC? Perhaps there is a way to get and analyze a core
> > file or a way to catch the exception and dump the heap and
> > garbage collector state. Any suggestions?
>
> Have you tried using the debugger?
>
> -- Damien
>
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Re: [Caml-list] Out_of_memory

[Damien Doligez]

On Dec 18, 2004, at 09:18, Christopher Alexander Stein wrote:

> Do you mean something more than gdb? I've used gdb and I get the
> following stack trace:

I mean ocamldebug.  It's well worth the investment of learning to use 
it.

> Program received signal SIGSEGV, Segmentation fault.

I'm not sure I understand how this segfault can translate to an
out-of-memory exception in the bytecode runtime.

-- Damien

Re: [Caml-list] Out_of_memory

[Christopher Alexander Stein]

Interesting point. It was throwing Out_of_memory half the time
and segfaulting the other half (in caml_oldify_mopup), then I
carefully read through the C <-> OCaml chapter of the manual and
made sure my C library code is consistent with the rules outlined
there. Since those changes, it no longer throws Out_of_memory and
always segfaults in caml_oldify_mopup. I will take a look at
camldebug.

Thanks,

Lex

On Sat, 18 Dec 2004, Damien Doligez wrote:

> > Program received signal SIGSEGV, Segmentation fault.
>
> I'm not sure I understand how this segfault can translate to an
> out-of-memory exception in the bytecode runtime.
>
> -- Damien
>
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