Refc binaries can be leaking when barely-busy processes route them around and do little else, or when extremely busy processes reach a stable amount of memory allocated and do the vast majority of their work with refc binaries. When this happens, it may take a very long while before references get deallocated and refc binaries get to be garbage collected, leading to out of memory crashes. This function fetches the number of refc binary references in each process of the node, garbage collects them, and compares the resulting number of references in each of them. The function then returns the n processes that freed the biggest amount of binaries, potentially highlighting leaks.

See the Erlang/OTP Efficiency Guide for more details on refc binaries.

Returns a list of all file handles open on the node.

Shorthand call to get_state(pid_term, 5000)

Fetch the internal state of an OTP process. Calls :sys.get_state/2 directly in OTP R16B01+, and fetches it dynamically on older versions of OTP.

Fetches a given attribute from all inet ports (TCP, UDP, SCTP) and returns the biggest num consumers.

The values to be used can be the number of octets (bytes) sent, received, or both (:send_oct, ~recv_oct, :oct, respectively), or the number of packets sent, received, or both (:send_cnt, :recv_cnt, :cnt, respectively). Individual absolute values for each metric will be returned in the 3rd position of the resulting tuple.

Fetches a given attribute from all inet ports (TCP, UDP, SCTP) and returns the biggest entries, over a sliding time window.

Warning: this function depends on data gathered at two snapshots, and then building a dictionary with entries to differentiate them. This can take a heavy toll on memory when you have many dozens of thousands of ports open.

The values to be used can be the number of octets (bytes) sent, received, or both (:send_oct, :recv_oct, :oct, respectively), or the number of packets sent, received, or both (:send_cnt, :recv_cnt, :cnt, respectively). Individual absolute values for each metric will be returned in the 3rd position of the resulting tuple.

Allows to be similar to :erlang.process_info/1, but excludes fields such as the mailbox, which have a tendency to grow and be unsafe when called in production systems. Also includes a few more fields than what is usually given (monitors, monitored_by, etc.), and separates the fields in a more readable format based on the type of information contained.

Moreover, it will fetch and read information on local processes that were registered locally (an atom), globally ({:global, name}), or through another registry supported in the {:via, module, name} syntax (must have a module.whereis_name/1 function). Pids can also be passed in as a string ("PID#<0.39.0>", "<0.39.0>") or a triple ({0, 39, 0}) and will be converted to be used.

Allows to be similar to :erlang.process_info/2, but allows to sort fields by safe categories and pre-selections, avoiding items such as the mailbox, which may have a tendency to grow and be unsafe when called in production systems.

Moreover, it will fetch and read information on local processes that were registered locally (an atom), globally ({:global, name}), or through another registry supported in the {:via, module, name} syntax (must have a module.whereis_name/1 function). Pids can also be passed in as a string ("#PID<0.39.0>", "<0.39.0>") or a triple ({0, 39, 0}) and will be converted to be used.

Although the type signature doesn’t show it in generated documentation, a list of arguments or individual arguments accepted by :erlang.process_info/2' and return them as that function would. A fake attribute:binary_memory` is also available to return the amount of memory used by refc binaries for a process.

Equivalent to info(<a.b.c>) where a, b, and c are integers part of a pid.

Equivalent to info(<a.b.c>, key) where a, b, and c are integers part of a pid.

Shorthand for named_rpc([node()|nodes()], fun)

Shorthand for named_rpc(nodes, fun, :infinity)

Runs an arbitrary fun (of arity 0) over one or more nodes, and returns the name of the node that computed a given result along with it, in a tuple.

Gathers statistics n time, waiting interval milliseconds between each run, and accumulates results using a folding function fold_fun. The function will gather statistics in two forms: Absolutes and Increments.

Absolutes are values that keep changing with time, and are useful to know about as a datapoint: process count, size of the run queue, error_logger queue length, and the memory of the node (total, processes, atoms, binaries, and ets tables).

Increments are values that are mostly useful when compared to a previous one to have an idea what they’re doing, because otherwise they’d never stop increasing: bytes in and out of the node, number of garbage collector runs, words of memory that were garbage collected, and the global reductions count for the node.

Shorthand for node_stats(n, interval, fn(x, acc) -> [x | acc] end, []) with the results reversed to be in the right temporal order.

Shorthand for node_stats(n, interval, fn(x, _) -> IO.inspect(x, pretty: true) end, :ok)

Allows to be similar to :erlang.port_info/1, but allows more flexible port usage: usual ports, ports that were registered locally (an atom), ports represented as strings ("#Port<0.2013>"),

or through an index lookup (2013, for the same result as "#Port<0.2013>").

Moreover, the function will try to fetch implementation-specific details based on the port type (only inet ports have this feature so far). For example, TCP ports will include information about the remote peer, transfer statistics, and socket options being used.

The information-specific and the basic port info are sorted and categorized in broader categories (port_info_type()).

Allows to be similar to :erlang.port_info/2, but allows more flexible port usage: usual ports, ports that were registered locally (an atom), ports represented as strings ("#Port<0.2013>"), or through an index lookup (2013', for the same result as”#Port<0.2013>”). Moreover, the function allows to to fetch information by category as defined inport_info_type(), and although the type signature doesn't show it in the generated documentation, individual items accepted by [:erlang.port_info/2`](http://www.erlang.org/doc/man/erlang.html#port_info-2) are accepted, and lists of them too.

Shows a list of all different ports on the node with their respective types.

Fetches a given attribute from all processes (except the caller) and returns the biggest num consumers.

Fetches a given attribute from all processes (except the caller) and returns the biggest entries, over a sliding time window.

This function is particularly useful when processes on the node are mostly short-lived, usually too short to inspect through other tools, in order to figure out what kind of processes are eating through a lot resources on a given node.

It is important to see this function as a snapshot over a sliding window. A program’s timeline during sampling might look like this:

--w---- [Sample1] ---x-------------y----- [Sample2] ---z--->

Some processes will live between w and die at x, some between y and z, and some between x and y. These samples will not be too significant as they’re incomplete. If the majority of your processes run between a time interval x…y (in absolute terms), you should make sure that your sampling time is smaller than this so that for many processes, their lifetime spans the equivalent of w and z. Not doing this can skew the results: long-lived processes, that have 10 times the time to accumulate data (say reductions) will look like bottlenecks when they’re not one.

Warning: this function depends on data gathered at two snapshots, and then building a dictionary with entries to differentiate them. This can take a heavy toll on memory when you have many dozens of thousands of processes.

Equivalent remote_load(nodes(), mod).

Loads one or more modules remotely, in a diskless manner. Allows to share code loaded locally with a remote node that doesn’t have it.

Shorthand for rpc([node()|nodes()], fun)

Shorthand for rpc(nodes, fun, :infinity)

Runs an arbitrary fn (of arity 0) over one or more nodes.

Because Erlang CPU usage as reported from top isn’t the most reliable value (due to schedulers doing idle spinning to avoid going to sleep and impacting latency), a metric exists that is based on scheduler wall time.

For any time interval, Scheduler wall time can be used as a measure of how busy a scheduler is. A scheduler is busy when:

• executing process code
• executing driver code
• executing NIF code
• executing BIFs
• garbage collecting
• doing memory management

A scheduler isn’t busy when doing anything else.

Returns a list of all SCTP ports (the data type) open on the node.

Obtain the source code of a module compiled with debug_info. The returned list sadly does not allow to format the types and typed records the way they look in the original module, but instead goes to an intermediary form used in the AST. They will still be placed in the right module attributes, however.

Returns a list of all TCP ports (the data type) open on the node.

Returns a list of all UDP ports (the data type) open on the node.