To provide the in-memory size of Erlang terms, ignoring where the Erlang terms are stored.
Size information should match the Erlang Efficiency Guide memory information:
- Small integer: 1 word
- On 32-bit architectures: -134217729 < i < 134217728 (28 bits)
- On 64-bit architectures: -576460752303423489 < i < 576460752303423488 (60 bits)
- Big integer: 3..N words
- Atom: 1 word
- Float:
- On 32-bit architectures: 4 words
- On 64-bit architectures: 3 words
- Binary: 3..6 + data
- List: 1 word + 1 word per element + the size of each element
- Tuple: 2 words + the size of each element
- Small Map (N =< 32): 5 words + the size of all keys and values
- Large Map (N > 32): N * [1.6 .. 1.8] + the size of all keys and values
- Pid:
- From local node: 1 word
- From remote node: 5 words
- Port:
- From local node: 1 word
- From remote node: 5 words
- Reference:
- On 32-bit architectures:
- From local node: 5 words
- From remote node: 7 words
- On 64-bit architectures:
- From local node: 4 words
- From remote node: 6 words
- On 32-bit architectures:
- Fun: 9..13 words + size of environment
- Erlang process: 338 words when spawned (includes a heap of 233 words)
- Binaries are not tracked to avoid counting a reference more than once (to avoid the extra latency and memory use)
MIT License
Michael Truog (mjtruog at protonmail dot com)
- Sverker Eriksson
erts_debug:flat_size/1info