Systemtap; Valgrind - Red Hat ENTERPRISE LINUX 5.5 - RELEASE NOTES 2010 Release Note

Release Notes
Independent thread debugging
Thread execution now permits debugging threads individually and independently of each other;
enabled by new settings "set target-async" and "set non-stop".

6.2. SystemTap

SystemTap is a tracing and probing tool that allows users to study and monitor the activities of the
operating system (particularly, the kernel) in fine detail. It provides information similar to the output of
tools like netstat, ps, top, and iostat; however, SystemTap is designed to provide more filtering and
analysis options for collected information.
New Kernel Tracepoints
Tracepoints are placed in important sections of the kernel, allowing system administrators to analyze
the performance of, and debug portions of code. In Red Hat Enterprise Linux 5.5, a wide range
of tracepoints have been added to the kernel
56
(BZ#475457)
, coredump
Note
A list of tracepoints available in the kernel can be obtained with:
stap -L 'kernel.trace("*")'|sort
Unprivileged mode
Previously, only users with root privileges were able to use SystemTap. This update introduces
SystemTap's unprivileged mode, allowing non-root users to still use SystemTap. Detailed information
on unprivileged man stap-client manpage.
Important
Unprivileged mode is considered a Technology Preview in the Red Hat Enterprise
Linux 5.5. The stap-server facility on which it relies is undergoing work for security
improvements and should be deployed with care on a trustworthy network.
C++ Probing
The C++ program probing improvements also allows better probing of user-space programs.

6.3. Valgrind

Valgrind is used to monitor memory read, write, and allocation operations. The valgrind tool is
frequently used by developers to diagnose and debug memory management problems.
55
https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=475710
56
https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=475457
57
https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=517115
58
https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=517121
10
(BZ#475710)
57
(BZ#517115)
and signal
55
, including tracepoints for networking
58
(BZ#517121)
.