Memory leak & slowdown

Memory leak & slowdown

[Dawid Toton]

I have an OCaml program using GTK running on Windows, using multiple 
threads.

The overall memory usage grows significantly over time, but I don't know 
why. After it consumes several MB extra, it slows considerably and 
becomes unusable, so I have to fix this.

Is it possible that this is related to GC compaction being turned off? 
Additional calls to Gc.compact seemingly don't help.

The memory usage grows only when the main processing loop is working. 
After the function exists, the memory is not freed. Moreover, if I start 
it again, it 'reuses' the leaked memory. The second execution of the 
loop takes more memory only after it takes more time than the previous one.

This made me thinking that it's just some container growing but not 
shrinking. So I checked my toplevel values with the objsize library, but 
I managed to trace down only a fraction of the allocated memory and the 
sizes I get don't grow.

How to do memory profiling?

The program can have about 10MB of useful data and 200MB of something I 
don't know. How to check what is this?

Dawid

Re: [Caml-list] Memory leak & slowdown

[Richard Jones]

On Fri, Jun 05, 2009 at 04:00:01PM +0200, Dawid Toton wrote:
> I have an OCaml program using GTK running on Windows, using multiple 
> threads.
> 
> The overall memory usage grows significantly over time, but I don't know 
> why. After it consumes several MB extra, it slows considerably and 
> becomes unusable, so I have to fix this.

Could this be the GtkListView / register_global_root problem
in lablgtk?

http://caml.inria.fr/pub/ml-archives/caml-list/2005/08/7468da0a1e9d9891bc4cdf13eb725a51.en.html

You might want to instrument the [caml_]register_global_root function
and see how often it gets called.

Rich.

-- 
Richard Jones
Red Hat

Re: Memory leak & slowdown

[Dawid Toton]

> 
> You might want to instrument the [caml_]register_global_root function
> and see how often it gets called.

Is it possible to enable profiling in the compiler in Windows or Cygwin 
environment? Cygwin has gprof, but OCaml's configure script says 'no 
profiling'.

Dawid

Re: Memory leak & slowdown

[Dawid Toton]

> The overall memory usage grows significantly over time, but I don't know 
> why. After it consumes several MB extra, it slows considerably and 
> becomes unusable, so I have to fix this.

I'm still unable to figure out what is the allocated memory, but I 
discovered few things:

* there is available (somewhat hidden) version of memprof patch that 
works with 3.10.0:
   http://www.pps.jussieu.fr/~smimram/docs/ocaml-3.10.0-memprof.patch
* It seems that I can't use gprof with OCaml programs in Windows


I can roughly remember I had memory leaks some time ago if I allocated 
big arrays in expose event handler (with lablgtk2) - still have to 
verify this.

Dawid