projects / lttng-docs.git / blame
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| 727aa690 PP |
1 | --- |
| 2 | id: whats-new | |
| 3 | --- | |
| 4 | ||
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5 | LTTng 2.7 ships with a generous list of new features, with essential |
| 6 | additions to all the project's components. | |
| 7 | ||
| 8 | Dynamic filtering of user space tracepoints has been available for | |
| 9 | quite some time now | |
| 10 | (see [Enabling and disabling events](#doc-enabling-disabling-events)). | |
| 11 | LTTng 2.7 adds filtering support to kernel events as well. For example: | |
| 12 | ||
| 13 | <pre class="term"> | |
| 14 | lttng enable-event --kernel irq_handler_entry --filter 'irq == 28' | |
| 15 | </pre> | |
| 16 | ||
| 71c82cd2 | 17 | LTTng 2.7 adds wildcard support for kernel event names: |
| 727aa690 PP |
18 | |
| 19 | <pre class="term"> | |
| 179d0464 | 20 | lttng enable-event --kernel 'sched_*' |
| 727aa690 PP |
21 | </pre> |
| 22 | ||
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23 | On the user space tracing side, the new [`tracelog()`](#doc-tracelog) |
| 24 | facility allows users to easily migrate from logging to tracing. | |
| 25 | `tracelog()` is similar to [`tracef()`](#doc-tracef), but accepts | |
| 26 | an additional log level parameter. | |
| 27 | ||
| 28 | The new `--shm-path` option of `lttng create` can be used to specify the | |
| 29 | path where the shared memory holding the ring buffers are | |
| 30 | created. This feature is useful when used with persistent memory file | |
| 31 | systems to extract the latest recorded trace data in the event of a | |
| 32 | crash requiring a reboot. The new `lttng-crash` command line | |
| 33 | utility can extract trace data from such a file (see | |
| 34 | [Recording trace data on persistent memory file systems](#doc-persistent-memory-file-systems)). | |
| 35 | ||
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36 | LTTng-UST 2.7 can rely on a user plugin to provide a custom clock source |
| 37 | to its tracer. LTTng-UST can also load a user plugin to retrieve the | |
| 38 | current CPU number. This feature exists for very advanced use cases. See | |
| 179d0464 PP |
39 | the <a href="https://github.com/lttng/lttng-ust/tree/master/doc/examples/clock-override" class="ext">clock-override</a> |
| 40 | and <a href="https://github.com/lttng/lttng-ust/tree/master/doc/examples/getcpu-override" class="ext">getcpu-override</a> | |
| 41 | examples for more details. | |
| 42 | ||
| 43 | Python developers can now benefit from the new | |
| 44 | [LTTng-UST Python agent](#doc-python-application), | |
| 45 | a Python 2/3-compatible package which allows standard Python logging | |
| 46 | using the `logging` module to output log entries to an LTTng trace. | |
| 47 | ||
| 48 | Last but not least, the new `lttng track` and `lttng untrack` commands | |
| 49 | make [<abbr title="process ID">PID</abbr> tracking](#doc-pid-tracking) | |
| 50 | super-fast for both the kernel and the user space domains. When one or | |
| 51 | more PIDs are tracked, only the processes having those PIDs are allowed | |
| 52 | to emit enabled events. | |
| 53 | ||
| 54 | Moreover, LTTng 2.7 boasts great stability, benifiting from piles of | |
| 55 | bug fixes and more-than-welcome internal refactorings. | |
| 26418fc3 | 56 | |
| 71c82cd2 | 57 | <!-- |
| 179d0464 PP |
58 | To learn more about the new features of LTTng 2.7, see |
| 59 | <a href="" class="ext">the release announcement</a>. | |
| 71c82cd2 | 60 | --> |