I'm glad to hear you're looking into this and I'm very interested to know what's going on.  My impression from watching this in action was simply that the head process seemed not so much to be hung up on something, but simply going much slower than the other processes until the time they finished, at which point it would speed up.  Parallel projections were where I saw this the most.  I have a feeling the effect was more noticeable the more processes you have.

One way I knew it was simply going slow and not actually hung up was that, when the other processes finished, I would be left with the progress bar of the route process, with an expected time of completion that was reading vary large.  However, it would quickly wind back down to something more reasonable as it would be speeding back up.

Sorry that isn't much help.  Good luck with this.  I'd really love to know what's going on here.

On Thu, Sep 24, 2009 at 11:35 AM, Stephen Skory <stephenskory@yahoo.com> wrote:

> Britton, Sam and Stephen have all reported to me at different times
> that it seems sometimes one of the processors in a parallel job hangs

I should add that the current problem I'm seeing and have been discussing with Matt appears to happen on all processors, not just one or the root. I may not have made that clear to him. But it may be related.

sskory@physics.ucsd.edu           o__  Stephen Skory
http://physics.ucsd.edu/~sskory/ _.>/ _Graduate Student
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