From: Marc L. Smith (mlsmith_at_colby_dot_edu)
Date: Mon Aug 15 2005 - 22:12:31 PDT
On Aug 15, 2005, at 9:51 PM, jcduell_at_lbl_dot_gov wrote: > This is because you're not using pthreads, so an executable statically > compiled for 8 UPC threads will use 8 processes, and thus needs 8 > entries > in your SSH_SERVERS/UPC_NODES. If you add -pthreads, you should be > OK: > > upcc -T 8 -pthreads helloworld2.upc > upcrun helloworld2 Thanks -- that worked! Wow -- sorry I completely missed the - pthreads option... (wasn't even on my radar screen) >> default_cpus_per_node = 2 >> (currently this is blank) >> > > This ought to work in theory for you example above, but I've just > discovered that it doesn't. I've added a bug (#1213) to our bugzilla > server about it. It probably won't be fixed by the release, though. > > Generally, you'll want to use -pthreads to get the best performance on > an SMP, and in that case this setting actually does work, so yes, you > probably want to set it (assuming all your nodes are 2-way SMPs). Glad to unknowingly help identify a bug to be fixed... Yes, all my nodes are dual Xeon boards, so I've set it. I added -pthreads to the upcc.conf file under default_options. I'm looking to simplify the command line options for my students as much as possible... >> udp_spawn_nodes = n1 n2 n3 n4 >> (currently, this is blank) >> > > This is not actually for providing a list of node names--it's the > command line that should be used when -nodes or -cpus-per-host is > passed > to upcrun. I believe that this should currently be "%P %N %A", > instead > of blank, but the only effect of having it be blank (for programs > compiled with -pthreads) is to cause some harmless warnings to be > emitted. I did have the harmless warnings: ~~~ upcrun: WARNING: Given options request 4 nodes for 4 processes, upcrun: WARNING: but there is no setting for 'udp_spawn_nodes'. upcrun: WARNING: Will use setting for 'udp_spawn' instead. upcrun: WARNING: THREAD LAYOUT MIGHT NOT MATCH YOUR REQUEST. ~~~ ...and as you promised, setting udp_spawn_nodes = "%P %N %A" to got rid of the warnings. Thanks again! > Thanks for rooting out these bugs! I feel it wasn't so much rooting as stumbling through, but thanks to your patience and help, I'm learning more about how UPC should be configured for my cluster -- so thank you! (and, you're welcome...) -Marc