Pmap performance regression: pmap(x->f(x,y), X) creates copies of y

General Usage Performance
9

I think this is a good suggestion.

For me the CachingPool version is comparable to the global version.

pool = CachingPool(workers())
pmap(pool, x->f_passall(x,bigarr), its)

Here’s my timings using Julia v0.6.4:

Julia-0.6.4> @btime pmap(x->f_passall(x,$bigarr), its);
  52.705 s (2176 allocations: 148.63 KiB)

Julia-0.6.4> @btime pmap(pool, x->f_passall(x,$bigarr), its);
  1.591 ms (1937 allocations: 124.23 KiB)

Julia-0.6.4> @btime pmap(x->f_globals(x), its);
  1.931 ms (1998 allocations: 134.13 KiB)