On Thu, Jun 23, 2011 at 04:26:41PM +0200, Bert Freudenberg wrote:
> I often get the Finalization process when I press Cmd-.
> 
> Usually I want the UI process. But it should be possible to break into
> a higher-level one too, if it takes much time. Not sure if this could
> be made more intelligent?

It's a bit of a tricky problem. The interrupt key gets noticed by the
VM, which signals the FinalizationSemaphore, which gets noticed by the
finalizationProcess, which needs to figure out what process was the
likely cause of the user hitting the interrupt key. It's not necessarily
the UI process, because the problem may have originated from e.g.
"[Smalltalk createStackOverflow] fork".

To me, the more interesting part of the problem is the fact that the
finalization process is frequently being selected as the process that
the user was "probably trying to interrupt". That means that the
finalization process is consuming so much processor resource that
it get interrupted instead of the actual process that the user intended
to interrupt with the Cmd-. key.

This seems to be typical of images that have accumulated a lot of
use and that tend to get sluggish over a long period of time. It
suggests some opportunity to improve the weak finalization process
overall. This is not a trivial problem by any means, and it has
been discussed before, but if I'm interpreting this correctly it
might be better to put some effort into trying to improve this,
as opposed to trying to make the user interrupt handler be smart
enough to avoid interrupting the finalizationProcess.

In terms of near-term improvements that might be possible, perhaps
it would help to have tools to reduce the amount of cruft that the
finalizationProcess needs to deal with. Various weak references
seem to accumulate over time, probably for no good reason, and
eventually this seems to lead to sluggish images and heavy loads
on the finalizationProcess.

- Dave