| 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 32/64-bit, and powerpc 32-bit at the moment). It should work fine with |
| 42 | newer kernels and other architectures, but expect build issues with kernels |
| 43 | older than 2.6.36. The clock source currently used is the standard gettimeofday |
| 44 | (slower, less scalable and less precise than the LTTng 0.x clocks). Support for |
| 45 | LTTng 0.x clocks will be added back soon into LTTng 2.0. Please note that |
| 46 | lttng-modules 2.0 can build on a Linux kernel patched with the LTTng 0.x |
| 47 | patchset, but the lttng-modules 2.0 replace the lttng-modules 0.x, so both |
| 48 | tracers cannot be installed at the same time for a given kernel version. |