Yes, that's what I meant. Presumably the multi-proc machinery is getting compiled at the first `using`. It's the same reason why "println(2+2)" is very slow on first use, but fast afterwards.
On Tue, Jul 19, 2016 at 10:41 AM, Marius Millea <mariusmil...@gmail.com> wrote: > Seems it may have something to do with that. If I understood correctly > what you're saying, if I create Empty2.jl defining module Empty2, I get, > > julia> addprocs(); > > julia> tic(); using Empty; toc() > elapsed time: 2.706353202 seconds > 2.706353202 > > julia> tic(); using Empty; toc() > elapsed time: 0.00042397 seconds > 0.00042397 > > julia> tic(); using Empty2; toc() > elapsed time: 0.029200919 seconds > 0.029200919 > > julia> tic(); using Empty2; toc() > elapsed time: 0.000193097 seconds > 0.000193097 > > > > That first load of Empty2 at 0.02 secs is much more in line with what > loading it on a single processor takes. > > > > On Tuesday, July 19, 2016 at 4:13:15 PM UTC+2, Cedric St-Jean wrote: >> >> Maybe there is some warm-up JIT time in there? If you create an Empty2 >> module and load it after Empty, is it also slow? >> >> On Tuesday, July 19, 2016 at 9:07:01 AM UTC-4, Marius Millea wrote: >>> >>> I noticed that once I addprocs(), subsequent "using" statements were >>> extremely slow. I guess in this case its loading the module on each >>> processor, but if it happens in parallel it shouldn't be *that* much more >>> wall time, and here I'm talking about two orders of magnitude difference. >>> >>> Assuming I've got a file Empty.jl who contents is, >>> >>> module Empty >>> end >>> >>> then single threaded: >>> >>> tic() >>> using Empty >>> toc() >>> elapsed time: 0.024461076 seconds >>> >>> vs. multi-threaded: >>> >>> addprocs() #I've got 8 procs >>> tic() >>> using Empty >>> toc() >>> elapsed time: 2.479418079 seconds >>> >>> >>> Should I submit this as an Issue on Github, or is there something else >>> going on? I've checked both Julia 0.4.5. and 0.5 (01e3c8a). I'm on Ubuntu >>> 16.04 64bit. >>> >>> >>>
