gist:46816bf50ec609104861

## original
% time ./rebar.old eunit suites=riak_cs_storage_mr_test skip_deps=true
Building riak-cs-ee
==> rel (eunit)
==> riak_cs-2.1 (eunit)
  All 50 tests passed.
Cover analysis: /home/shino/b/g/riak_cs-2.1/.eunit/index.html
./rebar.old eunit suites=riak_cs_storage_mr_test skip_deps=true  11.90s user 5.37s system 116% cpu 14.840 total

## cover disabled
% time ./rebar.old eunit suites=riak_cs_storage_mr_test skip_deps=true
Building riak-cs-ee
==> rel (eunit)
==> riak_cs-2.1 (eunit)
  All 50 tests passed.
./rebar.old eunit suites=riak_cs_storage_mr_test skip_deps=true  5.12s user 3.69s system 135% cpu 6.508 total

## +A 0 rebar + cover disabled
% time ./rebar.new eunit suites=riak_cs_storage_mr_test skip_deps=true
Building riak-cs-ee
==> rel (eunit)
==> riak_cs-2.1 (eunit)
  All 50 tests passed.
./rebar.new eunit suites=riak_cs_storage_mr_test skip_deps=true  2.89s user 0.38s system 135% cpu 2.414 total

comparison of ‘DEVNODES=1 make stagedevrel’

%% original
DEVNODES=1 make stagedevrel  28.74s user 26.43s system 126% cpu 43.689 total
%% new
DEVNODES=1 make stagedevrel  12.92s user 2.13s system 115% cpu 13.028 total
%% original again
DEVNODES=1 make stagedevrel  28.48s user 25.95s system 126% cpu 43.117 total
%% new again
DEVNODES=1 make stagedevrel  13.20s user 2.22s system 113% cpu 13.569 total

comparison of only generate

## original
% time ./rebar.old generate skip_deps=true
./rebar.old generate skip_deps=true  11.36s user 11.93s system 119% cpu 19.429 total

## new
% time ./rebar.new generate skip_deps=true
./rebar.new generate skip_deps=true  4.49s user 3.01s system 98% cpu 7.605 total

## original again
% time ./rebar.old generate skip_deps=true
./rebar.old generate skip_deps=true  10.99s user 11.20s system 121% cpu 18.267 total

## new again
% time ./rebar.new generate skip_deps=true
./rebar.new generate skip_deps=true  4.38s user 1.14s system 99% cpu 5.577 total

shino/gist:46816bf50ec609104861