On the KNL, what is a bus error (signal 7) as distinguished
from a seg fault (11)? I am getting these with (very) low
probability in OpenMP regions of my Fortran code. The same code
has worked fine for years on mira. Also on KNL the same
subroutines have been successfully invoked up to 100,000
times. But attempts to scale up to bigger runs are being
hit now.

Removing the !$OMP statements for the given
loop seems to get rid of the bus error, but of course
this slows the program down -- we have to be able to
use multithreading on this machine.

Steve

-- 
Steven C. Pieper, Senior Physicist Emeritus:                spieper@anl.gov 
Argonne National Laboratory, Physics Division, Bldg. 203, Argonne, IL 60439
Phone:  630-252-4232         Fax -6008        Secretary, Debra Beres, -4100
http://www.phy.anl.gov/theory/staff/scp.html