Why do these three loops perform so differently?
type MyCounter
i::Integer
end
up!(x::MyCounter) = (x.i += 1; x)
up!(x::Integer) = (x += 1; x)
cc = MyCounter(0)
dd = MyCounter(0)
ee = 0
@time for i in 1:1000000 up!(cc) end
@time for i in 1:1000000 dd.i=up!(dd.i) end
@time for i in 1:1000000 ee=up!(ee) end
With Version 0.3.0-prerelease+3841 (2014-06-22 11:24 UTC) I get:
julia> @time for i in 1:1000000 up!(cc) end
elapsed time: 0.25675581 seconds (31993864 bytes allocated)
julia> @time for i in 1:1000000 dd.i=up!(dd.i) end
elapsed time: 0.042308998 seconds (16003500 bytes allocated)
julia> @time for i in 1:1000000 ee=up!(ee) end
elapsed time: 0.022673645 seconds (15991824 bytes allocated)
Especially I don't understand why there is so much overhead going from
first to second.
Thanks!
