Hi Hesam, According to an earlier work of our ALCF Catalyst, using a combination of -O3 and -qhot was improving the performance in previous generations of BG/Q compilers so further testing could be helpful. Best. Aleks ----- Original Message ----- From: [email protected] To: [email protected] Sent: Tuesday, October 15, 2013 3:56:20 PM Subject: [Nek5000-users] Compilation flags on BG/Q Dear Neks I was wondering if anyone here could give me the recommended set of compilers and flags for running nek on BG/Q so that I could modify makenek. I guess the experienced users of Mira could be of great help. Regards, Hesam _______________________________________________ Nek5000-users mailing list [email protected] https://lists.mcs.anl.gov/mailman/listinfo/nek5000-users