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XPLOR 3.851 under OSF fails to use multiple processors?

Ethan A Merritt merritt at u.washington.edu
Fri May 16 23:39:12 EST 1997


I have finally gotten around to installing version 3.851, and in running
it through its paces have noticed something I do not understand.
I am generally running on a DEC Alpha SMP multiprocessor, and use the
DXML version of the code (osftime_dxml.s).  XPLOR 3.1, which I have
been running up until now, happily takes advantage of the multiple
CPU's, typically showing a load of ~195% with the environmental variable
PARALLEL set to 2.

Version 3.851, however, fails to go above 100% (i.e. it never grabs more
than one CPU).  I can see that the FFT calls have changed somewhat 
between 3.1 and 3.851, but they both invoke DXML routines so they should
get the same benefit of the parallel processing DXML library.
So what gives?  Is this known behaviour?  It's a bit annoying to lose
50% in execution speed relative to the older version.  Has anyone else
noticed this, or [better yet] can anyone confirm that 3.851 does indeed
work on an SMP machine and that I must just have done something dumb
during installation?

				thanks for any insight,

					Ethan A Merritt
					merritt at u.washington.edu






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