[FLASH-USERS] Flash4b hangs on BlueGene/Q system

[Mirko Cestari]

Dear Chris, all,
thanks for the feedback. Indeed the problem is the "-cpp"
treated as -c -p -p by the compiler. Sorry, my bad! I noticed
that -cpp was not an argument of bgxlf but I could not relate it
to the profile "-p" flag (that argument was left in the Makefile
provided by the user, or maybe in the distribution?, 
I wonder if the problems of flash4 on Juqueen are related).     

Anyway I got rid of the flag, fixed a couple of other issues 
and now it seems everything is working. 


> Notice that when I include '-cpp' I get the '_mcount' symbol in the
> object file.  You should remove the '-cpp' option from your compile
> line.  Even better would be to download FLASH4.0 and base your
> Makefile.h on ./sites/miralac1/Makefile.h.  This should allow you to
> run FLASH on your BG/Q.

great, that's good news. I'll definitely try this out. 

> Normally these profiling symbols should not cause any problems,
> however, keep in mind that the BG/Q is still very new and weird issues
> can crop up.  In the last year we have had early access to the BG/Q at

I tried to profile a couple of times on BGQ and this "hang" issue 
didn't come up.

> Argonne National Lab and I have also had an issue with gprof
> profiling.  I did not have the hang that you are encountering but I
> had an issue where 0 samples were recorded during gprof profiling.
> Someone at Argonne National Lab had the same issue and advised me to
> link against an old version of libc.a at an earlier efix level so that
> I could continue with gprof profiling (the mcount symbols exist in
> libc.a.).  Perhaps the issues are related?

interesting, I might ask my sys-admins if they have an older version of 
libc.a to link against and see if the hang remains.

> Chris

Thanks a lot Chris!

Mirko