[lttng-modules.git] / README

LTTng 2.0 modules

Mathieu Desnoyers
July 19, 2011

LTTng 2.0 kernel modules build against a vanilla or distribution kernel, without
need for additional patches. Other features:

- Produces CTF (Common Trace Format) natively,
  (http://www.efficios.com/ctf)
- Tracepoints, Function tracer, CPU Performance Monitoring Unit (PMU)
  counters and kprobes 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).
  All the extra information fields to be collected with events are
  optional, specified on a per-tracing-session basis (except for
  timestamp and event id, which are mandatory).

To build and install, you will need to have your kernel headers available (or
access to your full kernel source tree), and use:

% make
# make modules_install

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

Use lttng-tools to control the tracer. LTTng tools should automatically load
the kernel modules when needed. Use Babeltrace to print traces as a
human-readable text log. These tools are available at the following URL:
http://lttng.org/lttng2.0

Please note that the LTTng-UST 2.0 (user-space tracing counterpart of LTTng 2.0)
is still in active development and not released yet.

So far, it has been tested on vanilla Linux kernels 2.6.38, 2.6.39 and 3.0-rc7
(on x86 at the moment). It should work fine with newer kernels and other
architectures, but expect build issues with kernels older than 2.6.36. The clock
source currently used is the standard gettimeofday (slower, less scalable and
less precise than the LTTng 0.x clocks). Support for LTTng 0.x clocks will be
added back soon into LTTng 2.0. Please 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.
Commit	Line	Data
98541fcf MD	1	LTTng 2.0 modules
	2
	3	Mathieu Desnoyers
	4	July 19, 2011
	5
	6	LTTng 2.0 kernel modules build against a vanilla or distribution kernel, without
	7	need for additional patches. Other features:
	8
	9	- Produces CTF (Common Trace Format) natively,
	10	(http://www.efficios.com/ctf)
fe178379 MD	11	- Tracepoints, Function tracer, CPU Performance Monitoring Unit (PMU)
fe178379 MD	12	counters and kprobes support,
98541fcf MD	13	- Integrated interface for both kernel and userspace tracing,
98541fcf MD	14	- Have the ability to attach "context" information to events in the
fe178379 MD	15	trace (e.g. any PMU counter, pid, ppid, tid, comm name, etc).
	16	All the extra information fields to be collected with events are
	17	optional, specified on a per-tracing-session basis (except for
	18	timestamp and event id, which are mandatory).
98541fcf MD	19
	20	To build and install, you will need to have your kernel headers available (or
	21	access to your full kernel source tree), and use:
	22
6b408629 MD	23	% make
6b408629 MD	24	# make modules_install
98541fcf MD	25
	26	If you need to specify the target directory to the kernel you want to build
	27	against, use:
	28
6b408629 MD	29	% KERNELDIR=path_to_kernel_dir make
6b408629 MD	30	# KERNELDIR=path_to_kernel_dir make modules_install
98541fcf	31
6b408629 MD	32	Use lttng-tools to control the tracer. LTTng tools should automatically load
	33	the kernel modules when needed. Use Babeltrace to print traces as a
	34	human-readable text log. These tools are available at the following URL:
	35	http://lttng.org/lttng2.0
bd2fc8af MD	36
	37	Please note that the LTTng-UST 2.0 (user-space tracing counterpart of LTTng 2.0)
	38	is still in active development and not released yet.
98541fcf	39
14a8117f MD	40	So far, it has been tested on vanilla Linux kernels 2.6.38, 2.6.39 and 3.0-rc7
	41	(on x86 at the moment). It should work fine with newer kernels and other
	42	architectures, but expect build issues with kernels older than 2.6.36. The clock
	43	source currently used is the standard gettimeofday (slower, less scalable and
	44	less precise than the LTTng 0.x clocks). Support for LTTng 0.x clocks will be
	45	added back soon into LTTng 2.0. Please note that lttng-modules 2.0 can build on
	46	a Linux kernel patched with the LTTng 0.x patchset, but the lttng-modules 2.0
	47	replace the lttng-modules 0.x, so both tracers cannot be installed at the same
	48	time for a given kernel version.