However, when I btime the “singlethread” method, with the same data frame object of 10mm rows, there is no change on my windows memory monitor, it was a flat line, meaning there is no memory re-allocation.
both multithread and single thread method are reading the same large dataset and doing the exact same operation to do cumsum.
i just don’t understand why single thread seems to make my windows memory “Not Grow at all”, while the multithread method, make it grow, as below two graph shows:
On a separate note, i find that accessing data frame with df[j][i] is not a good choice, because there is type instability! that’s why it is allocating huge amount of memory.
I will try again by creating a 10m row, 10 column simple Array{Float64, 2} to test.
then i have no memory allocation at all…