- Produces CTF (Common Trace Format) natively,
(http://www.efficios.com/ctf)
- Tracepoints, Function tracer, CPU Performance Monitoring Unit (PMU)
- counters and kprobes support,
+ counters, kprobes, and kretprobes support,
- Integrated interface for both kernel and userspace tracing,
- Have the ability to attach "context" information to events in the
trace (e.g. any PMU counter, pid, ppid, tid, comm name, etc).
% make
# make modules_install
+# depmod -a
If you need to specify the target directory to the kernel you want to build
against, use:
% KERNELDIR=path_to_kernel_dir make
# KERNELDIR=path_to_kernel_dir make modules_install
+# depmod -a kernel_version
Use lttng-tools to control the tracer. LTTng tools should automatically load
the kernel modules when needed. Use Babeltrace to print traces as a
note that lttng-modules 2.0 can build on a Linux kernel patched with the LTTng
0.x patchset, but the lttng-modules 2.0 replace the lttng-modules 0.x, so both
tracers cannot be installed at the same time for a given kernel version.
+
+* Note about Perf PMU counters support
+
+Each PMU counter has its zero value set when it is attached to a context with
+add-context. Therefore, it is normal that the same counters attached to both the
+stream context and event context show different values for a given event; what
+matters is that they increment at the same rate.