You can set the following entry inside the conf/spark-defaults.conf file spark.cores.max 16
If you want to read the default value, then you can use the following api call *sc*.defaultParallelism where *sc* is your sparkContext object. Thanks Best Regards On Sun, Nov 9, 2014 at 6:48 PM, ReticulatedPython <person.of.b...@gmail.com> wrote: > So, I'm running this simple program on a 16 core multicore system. I run it > by issuing the following. > > spark-submit --master local[*] pi.py > > And the code of that program is the following. When I use top to see CPU > consumption, only 1 core is being utilized. Why is it so? Seconldy, spark > documentation says that the default parallelism is contained in property > spark.default.parallelism. How can I read this property from within my > python program? > > #"""pi.py""" > from pyspark import SparkContext > import random > > NUM_SAMPLES = 12500000 > > def sample(p): > x, y = random.random(), random.random() > return 1 if x*x + y*y < 1 else 0 > > sc = SparkContext("local", "Test App") > count = sc.parallelize(xrange(0, NUM_SAMPLES)).map(sample).reduce(lambda a, > b: a + b) > print "Pi is roughly %f" % (4.0 * count / NUM_SAMPLES) > > > > -- > View this message in context: > http://apache-spark-user-list.1001560.n3.nabble.com/Why-does-this-siimple-spark-program-uses-only-one-core-tp18434.html > Sent from the Apache Spark User List mailing list archive at Nabble.com. > > --------------------------------------------------------------------- > To unsubscribe, e-mail: user-unsubscr...@spark.apache.org > For additional commands, e-mail: user-h...@spark.apache.org > >