NAME¶

threadsnoop.bt - Trace thread creation via pthread_create(). Uses bpftrace/eBPF.

SYNOPSIS¶

threadsnoop.bt

DESCRIPTION¶

threadsnoop traces calls to pthread_create(), showing this path of thread creation. This can be used for workload characterization and discovery, and is a companion to execsnoop.bt(8) which traces execve(2).

This works by tracing the pthread_create() from libpthread.so.0. The path to this library may need adjusting in the tool source to match your system.

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

REQUIREMENTS¶

CONFIG_BPF and bpftrace.

EXAMPLES¶

Trace calls pthread_create():

# threadsnoop.bt

FIELDS¶

TIME(ms)

Elapsed time since the tool began tracing (in milliseconds).

PID

The process ID.

COMM

The process (thread) name.

FUNC

The name of the start routine, if the symbol is available, else a hex address for the start routine address.

OVERHEAD¶

Thread creation is expected to be low (<< 1000/s), so the overhead of this tool is expected to be negligible.

SOURCE¶

This tool originated from the book "BPF Performance Tools", published by Addison Wesley (2019):

http://www.brendangregg.com/bpf-performance-tools-book.html

See the book for more documentation on this tool.

This version is in the bpftrace repository:

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.

OS¶

Linux

STABILITY¶

Unstable - in development.

AUTHOR¶

Brendan Gregg

SEE ALSO¶

execsnoop.bt(8)