How to calculate the size of an Erlang process in memory?

Question

I have a 'worker' process which I am going to assign to a job. Before I spawn hundreds of processes of this type I would like to know the memory consumption figures for it.

I know that I should sum all the elements which are stored in the process' loop data (all tuples, atoms, lists, etc) and the actual process memory footprint.

As I understand, before doing that I have to know the actual size of a {tuple|atom|list|process} itself.

Given a certain data structure which is stored in the process' memory how can I calculate the overall size of the process in memory?

Answer 1

erlang:process_info/2 will give you the amount of memory, in bytes, that a process occupies. For example:

1> erlang:process_info(whereis(code_server), memory).
{memory,284208}

Note that binaries are not included since they are not located in the process heap. Those you have to count the size of manually.

Answer 2

Did you read the Erlang Efficiency Guide on Memory?