README

   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)
  11 - Tracepoints, Function tracer, CPU Performance Monitoring Unit (PMU)
  12   counters and kprobes support,
  13 - Integrated interface for both kernel and userspace tracing,
  14 - Have the ability to attach "context" information to events in the
  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).
  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
  23 % make
  24 # make modules_install
  25
  26 If you need to specify the target directory to the kernel you want to build
  27 against, use:
  28
  29 % KERNELDIR=path_to_kernel_dir make
  30 # KERNELDIR=path_to_kernel_dir make modules_install
  31
  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
  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.
  39
  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.