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From <...@covalent.net>
Subject Re: Suggested direction for fixing threaded mpm thread startup.
Date Mon, 16 Apr 2001 20:58:30 GMT

> >> Sorry I was thinking "overlaying the scoreboard" when I wrote "creating
> >> new scoreboard entry" and no the latter is not the way to do that. The
> >> former  minimizes the amount of scoreboard-type data being kept outside
> >> the scoreboard.
> >
> > The problem with overlaying the scoreboard, is that you have to
> > introduce
> > synchronization in order to do it.  You also need to modify how
> > processes
> > figure out where to store their scoreboard entries.  As soon as you
> > move a
> > scoreboard entry from it's default location to a new place in the
> > scoreboard, you are introducing a big headache.
> >
>
> Mmm, was thinking not of moving within the scoreboard, just copy out the
> few active threads with the old dying process and copy over all those
> entries for new.
>
> Must be synchronous, as you point out.
>
> Can your idea handle broken processes with a couple of hung threads? Is
> there a whole temp scoreboard, or just the overflow processes?

There is just the one scoreboard, and the parent basically scans through
the entire scoreboard, looking for the longest run of contiguous blocks.
Once it has that number, it creates a child process that has that number
of threads.  In order to do this, it will need to modify a couple of
values before forking, and then reset them to the original values.

The only problem I see, is if all of the processes have a large number of
hung threads.  I am not sure that is a situation we need to fix though.
If all of your processes are hung, we have the same issue.

Ryan

_______________________________________________________________________________
Ryan Bloom                        	rbb@apache.org
406 29th St.
San Francisco, CA 94131
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