Example scripts for User-space, Statically Defined Tracing (USDT)
=================================================================

This directory contains scripts showcasing User-space, Statically Defined
Tracing (USDT) support for Bitcoin Core on Linux using. For more information on
USDT support in Bitcoin Core see the [USDT documentation].

[USDT documentation]: ../../doc/tracing.md


Examples for the two main eBPF front-ends, [bpftrace] and
[BPF Compiler Collection (BCC)], with support for USDT, are listed. BCC is used
for complex tools and daemons and `bpftrace` is preferred for one-liners and
shorter scripts.

[bpftrace]: https://github.com/iovisor/bpftrace
[BPF Compiler Collection (BCC)]: https://github.com/iovisor/bcc


To develop and run bpftrace and BCC scripts you need to install the
corresponding packages. See [installing bpftrace] and [installing BCC] for more
information. For development there exist a [bpftrace Reference Guide], a
[BCC Reference Guide], and a [bcc Python Developer Tutorial].

[installing bpftrace]: https://github.com/iovisor/bpftrace/blob/master/INSTALL.md
[installing BCC]: https://github.com/iovisor/bcc/blob/master/INSTALL.md
[bpftrace Reference Guide]: https://github.com/iovisor/bpftrace/blob/master/docs/reference_guide.md
[BCC Reference Guide]: https://github.com/iovisor/bcc/blob/master/docs/reference_guide.md
[bcc Python Developer Tutorial]: https://github.com/iovisor/bcc/blob/master/docs/tutorial_bcc_python_developer.md

## Examples

The bpftrace examples contain a relative path to the `bitcoind` binary. By
default, the scripts should be run from the repository-root and assume a
self-compiled `bitcoind` binary. The paths in the examples can be changed, for
example, to point to release builds if needed. See the
[Bitcoin Core USDT documentation] on how to list available tracepoints in your
`bitcoind` binary.

[Bitcoin Core USDT documentation]: ../../doc/tracing.md#listing-available-tracepoints

**WARNING: eBPF programs require root privileges to be loaded into a Linux
kernel VM. This means the bpftrace and BCC examples must be executed with root
privileges. Make sure to carefully review any scripts that you run with root
privileges first!**