erlang_pmp

Poor Man's Profiler inspired Erlang profiler.

Running

erlang_pmp:profile(Opts).

Opts

• duration: duration the profiling will run for, in seconds (default: 60).
• processes: list of PIDs that will be profiled, or all to use erlang:processes() before taking each sample (default: all).
• sleep: sleep duration in milliseconds between taking samples (default: 10).
• show_pid: if true, PID (or process name if registered) will be prepended to the stack trace (default: false).
• filename: path under which the profiling results will be saved (default: /tmp/erlang_pmp.trace).
• include_statuses: a list of process statuses as returned from erlang:process_info(Pid, status). A stack trace will only be counted if the process status belongs to the list, or if include_statuses is all (default: all).
• show_status: if true, status of the process will be appended to the stack trace (default: false)

Output

The output of erlang_pmp is meant to be used with FlameGraph stack trace visualizer:

git clone https://github.com/brendangregg/FlameGraph.git
FlameGraph/flamegraph.pl /tmp/erlang_pmp.trace > /tmp/erlang_pmp.svg

Examples

First it is good to increase the depth of captured call stacks, which by default are 8 frames only.

erlang:system_flag(backtrace_depth, 128).

The below example is useful in scenarios when we want to sample all processes to get an idea of the overall system profile. We omit the waiting state to focus on busy processes only.

erlang_pmp:profile([{duration, 30}, {include_statuses, [exiting, garbage_collecting, running, runnable, suspended]}, {show_status, true}, {show_pid, true}]).

If the system has many processes, we sample stacks less frequently and don't show individual pids:

erlang_pmp:profile([{duration, 30}, {include_statuses, [exiting, garbage_collecting, running, runnable, suspended]}, {show_status, true}, {sleep,50}]).