[Yt-dev] Parallel Processes Hanging

[Matthew Turk]

Hi Britton,

Thanks for your information.  My suspicion is that there might be
something going on with the IO.  I've committed a change (r1460) that
reduces IO on non-root processors -- and also warns if your loglevel
threshold is too low -- and hopefully this will help with things.  In
retrospect, there really WAS a lot of IO on the processors, and the
progressbars only made it worse!

If you get a chance to test this, let me know!

-Matt

On Fri, Sep 25, 2009 at 8:30 AM, Britton Smith <brittonsmith at gmail.com> wrote:
> 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 at yahoo.com>
> wrote:
>>
>> Yo,
>>
>>
>> > 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 at physics.ucsd.edu           o__  Stephen Skory
>> http://physics.ucsd.edu/~sskory/ _.>/ _Graduate Student
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