Re: gobject patch to track memory use

[Federico Mena Quintero <federico ximian com>]

On Thu, 2005-02-24 at 18:23 +0100, Alexander Larsson wrote:
> I spent some day today hacking up a patch to gobject that lets you track
> what types of GObjects are using memory.
> 
> It keeps a list of all live objects, and when you send the process a
> SIGUSR2 it prints a memory profile. For the size it counts the basic
> size of the object plus all private data registered with the object. 
> 
> Furthermore it adds some API that lets you register a function to
> calculate the size an object uses. This is useful for objects that own
> memory allocations that are not GObjects. I also made a gtk+ patch using
> this to track the real size of GdkPixbuf object.

This is very nice!  Memprof only shows you mallocs grouped by stack
trace, but sometimes you need the aggregated size of an object as it
grows from auxiliary functions.

I wonder if this patch could be obviated somehow by enhancing the
memprof GUI to let you group related functions together.  So, you would
group

   foo_object_new()
   foo_object_grow_some_internal_buffer()
   foo_object_add_string()
   ... etc ...

> Even without specific functions for all types this is quite useful, as
> you can see the object counts. I've already detected some strange things
> in nautilus with this. The top of the memory profile there looks like:
> 
> GtkImage: 231 allocated at 104 base size bytes, 23 kb total size
> GstPadTemplate: 334 allocated at 76 base size bytes, 24 kb total size
> GtkSeparatorMenuItem: 284 allocated at 96 base size bytes, 26 kb total size
> NautilusIconCanvasItem: 502 allocated at 64 base size bytes, 31 kb total size
> GtkAccelLabel: 306 allocated at 168 base size bytes, 50 kb total size
> NautilusVFSFile: 1005 allocated at 128 base size bytes, 296 kb total size
> GdkPixbuf: 340 allocated at 52 base size bytes, 6409 kb total size

What's the strange thing you detected?  Just curious.

It may be nice to enable this patch if you compile glib with
--enable-debug.

  Federico