README

MUTRACE Mutex Tracer

This is a personal fork of Lennart Poeterring's work
GIT:
        git://git.0pointer.de/mutrace.git

GITWEB:
        http://git.0pointer.de/?p=mutrace.git

NOTES:
        For a terse overview what mutrace can do for you, please read
        the announcement blog story:

        http://0pointer.de/blog/projects/mutrace.html

        The tarball includes two profilers:

        mutrace profiles lock contention for you. Just use it as
        prefix for your usual command line and it will profile
        mutexes used in all child processes. Example:

                mutrace gedit

        matrace traces memory allocation operations in realtime
        threads for you. It is of no use in applications that do not
        make use of realtime scheduling. Example:

                matrace myrealtimetool

       Both tools understand a --debug-info switch in which case the
       backtraces generated will include debugging information such as
       line numbers and source file names. This is not enabled by
       default since generating those traces is not always safe in
       situations where locks are taken or memory allocated as we do
       it here. YMMV.

       mutrace cannot be used to profile glibc-internal mutexes.

LICENSE:
        LGPLv3+

        Exception:

        backtrace-symbols.c is GPLv2+. Which probably means that using
        the --debug-info switch for mutrace and matrace might not be
        legally safe for non-GPL-compatible applications. However,
        since that module is independantly built into a seperate .so
        it should still be safe using the profilers without this
        switch on such software.

AUTHORS:
        Lennart Poettering

REQUIREMENTS:
        Recent gcc, glibc, Linux

KNOWN ISSUES:
        On Ubuntu 14.04, libiberty package has been modified.
	Install package libiberty-dev instead of binutils-dev.
	Also note libiberty includes have moved from
	/usr/include to /usr/include/libiberty. You may need to
	change the include directive in backtrace-symbols.c and
	/usr/include/bfd.h.

	When using --full-bt options, you may need to send USR1
	signal to mutrace instead of simply exiting the process,
	as the full debug info may not be available any longer.