Hi,
Am 27.08.2014 um 17:33 schrieb Michael Dietrich: > Hello, > > I am using X10 as a part of my bachelor's thesis about high > performance programming languages (so maybe some more questions may be > asked later :-) ). > > My first questions are about using several places: > > * If I set X10_NPLACES=n with having less than n hosts, the places > will be distributed among the existing hosts, right? "[...] Both of the above will wrap if there are more places than hostnames specified. For example, setting X10_NPLACES=4 and X10_HOSTLIST=host1,host2 will cause places 0 and 2 to run on host1, and places 1 and 3 to run on host2. If neither of the above is set, and there is more than 1 place, then it defaults to running everything on localhost.[...]" (http://x10-lang.org/documentation/practical-x10-programming/x10rt-implementations.html) > > * Is there a possibility to find out which place is located on which > host? In Chapel you have here.name. > http://x10.sourceforge.net/x10doc/latest/x10/lang/Runtime.html#getName%28%29 (Just a suggestion, never tried it) > * Should X10_NTHREADS be equal to the amount of cores within a host? > First, you should know, that the X10RT is allowed to create more than the specified amount of threads, if needed. X10_NTHREADS is the amount of threads, with wich each place starts (http://x10-lang.org/home/faq-list.html#FAQ-HowdoIcontrolthesizeofthethreadpoolinaplace%3F). Additional threads may be created from the x10RT. You can see, when threads are created by using X10_WARN_ON_THREAD_CREATION (may flood your console). To lock the number of threads to X10_NTHREADS, you can use X10_STATIC_THREADS (http://x10.sourceforge.net/documentation/languagespec/x10-env.pdf, Page 6), but that is not recommended, since it can screw with the runtime a lot (http://sourceforge.net/p/x10/mailman/x10-users/thread/OF5DE2C79E.C57B0F28-ON85257CE5.004E934D-85257CE5.004F8CFC%40us.ibm.com/#msg32386009). Second, knowing that, it depends on the given scenario. If you run more than one place per clusternode, i do not think, that you will get any performance boost. When you run two places per node and the machine has eight (pyhsical) cores, you may wish to give each place four threads. > * Let there be X10_HOSTLIST="A,B,foo". A and B are the hosts I want to > use while foo is a randomly chosen set of letters for simulating a > mistyped or currently inactive computer. > If I start a program with this parameter I don't get an error message > though there is something wrong. If I do isDead() on every place every > of them returns false. > Did I maybe forget to set something so it doesn't distribute the > places to other computers or does X10 ignore host names which cannot > be reached? > No idea honestly, but i am quite interested in the answer. I hope i was of some help =) Cheers, Marco > Thank you very much > bye > > > ------------------------------------------------------------------------------ > Slashdot TV. > Video for Nerds. Stuff that matters. > http://tv.slashdot.org/ > _______________________________________________ > X10-users mailing list > X10-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/x10-users > ------------------------------------------------------------------------------ Slashdot TV. Video for Nerds. Stuff that matters. http://tv.slashdot.org/ _______________________________________________ X10-users mailing list X10-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/x10-users
