Here is a parallel program: M = [rand(1000,1000) for i=1:16] @time pmap(svd, M)
Here are timing results for local workers on a 16 core machine1: julia -p 2: 14.98 secs julia -p 4: 16.02 secs julia -p 8: 17.64 secs Here are timing results for machine1 connecting to remote workers on same type of machine2: julia --machinefile <2 copies of machine2>: 11.75 secs julia --machinefile <4 copies of machine2>: 7.54 secs julia --machinefile <8 copies of machine2>: 6.46 secs At first I thought things got messed up if the master and the slaves were on the same machine. But it turns out the difference is between -p <n> vs. --machinefile. If I rerun the same test on a single machine, but use --machinefile instead of -p n: julia --machinefile <2 copies of machine1>: 8.41 secs julia --machinefile <4 copies of machine1>: 4.70 secs julia --machinefile <8 copies of machine1>: 3.31 secs I am using Julia Version 0.3.9 (2015-05-30 11:24 UTC). Why is -p n messed up? thanks, deniz
