NAME¶

pidpersec.bt - Count new processes (via fork()). Uses bpftrace/eBPF.

SYNOPSIS¶

pidpersec.bt

DESCRIPTION¶

pidpersec shows how many new processes were created each second. There can be performance issues caused by many short-lived processes, which may not be visible in sampling tools like top(1). pidpersec provides one way to investigate this behavior.

This works by tracing the tracepoint:sched:sched_process_fork tracepoint.

Since this uses BPF, only the root user can use this tool.

REQUIREMENTS¶

CONFIG_BPF and bpftrace.

EXAMPLES¶

Count new processes, printing per-second summaries until Ctrl-C is hit:

# pidpersec.bt

FIELDS¶

1st

Count of processes (after "@")

OVERHEAD¶

This traces kernel forks, and maintains an in-kernel count which is read asynchronously from user-space. As the rate of this is generally expected to be low (<< 1000/s), the overhead is also expected to be negligible.

SOURCE¶

This is from bpftrace.

https://github.com/iovisor/bpftrace

Also look in the bpftrace distribution for a companion _examples.txt file containing example usage, output, and commentary for this tool.

This is a bpftrace version of the bcc tool of the same name. The bcc tool may provide more options and customizations.

https://github.com/iovisor/bcc

OS¶

Linux

STABILITY¶

Unstable - in development.

AUTHOR¶

Brendan Gregg

SEE ALSO¶

top(1)