Re: 2nd beta preview looking good!

From: Marc L. Smith (mlsmith_at_colby_dot_edu)
Date: Mon Aug 15 2005 - 22:12:31 PDT

  • Next message: jcduell_at_lbl_dot_gov: "Berkeley UPC beta release 2"
    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.
    ...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...)

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