[lttng-dev] [RELEASE] LTTng-UST 2.9.7 (EOL), 2.10.6 (Linux user-space tracer)
Hi, We are pleased to announce the 2.9.7 (EOL) and 2.10.6 stable releases of the LTTng-UST 2.9 and 2.10 stable branches. LTTng-UST, the Linux Trace Toolkit Next Generation Userspace Tracer, is a low-overhead application tracer. The library "liblttng-ust" enables tracing of applications and libraries. * New in this release: Important fixes to the lttng-ust fd tracker (liblttng-ust-fd.so) were done, taking care of locking the fd tracker across fork() in the liblttng-ust-fork.so wrapper, eliminating hangs observed in the child if the parent was executing close() concurrently with fork(). Also, given that close() is an async-signal-safe function, ensure that the synchronization strategy is robust against signals by disabling signals and using a TLS nesting counter when taking the fd tracker lock. [1, 2] Another important fix to the lttng-ust fd tracker is disabling thread cancellation around fd tracker lock, and locking the fd tracker across fork() in the liblttng-ust-fork.so wrapper. Failure to do so causes deadlocks in child applications if a pthread cancellation is performed on a thread while it ran the liblttng-ust-fd close(3) wrapper. [3] The locking strategy of the LTTng perf counter contexts was revisited to eliminate a deadlock occurring once in a while when using the perf counters context with lttng-ust. [4] Now that the release of LTTng-UST 2.11.0 is imminent, version 2.9.7 marks the end of life (EOL) of the 2.9 stable branch of LTTng-UST. Thanks! Mathieu Project website: http://lttng.org Documentation: http://lttng.org/docs Download link: http://lttng.org/download [1] https://bugs.lttng.org/issues/1199 [2] https://bugs.lttng.org/issues/1200 [3] https://bugs.lttng.org/issues/1201 [4] https://bugs.lttng.org/issues/1202 -- Mathieu Desnoyers EfficiOS Inc. http://www.efficios.com ___ lttng-dev mailing list lttng-dev@lists.lttng.org https://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev
[lttng-dev] [RELEASE] LTTng-modules 2.9.15 (EOL), 2.10.12 (Linux kernel tracer)
Hi, We are pleased to announce the 2.9.15 (EOL) and 2.10.12 stable releases of the LTTng-modules project 2.9 and 2.10 stable branches. The LTTng modules provide Linux kernel tracing capability to the LTTng tracer toolset. * New in these release: Both releases contain an update the the scheduler "prev_state" field of the sched_switch event. It now traces payload which matches the various changes that went through the various upstream Linux kernel versions. Now that the release of LTTng-modules 2.11.0 is imminent, version 2.9.15 marks the end of life (EOL) of the 2.9 stable branch of LTTng-modules. Thanks! Mathieu Project website: http://lttng.org Documentation: http://lttng.org/docs Download link: http://lttng.org/download -- Mathieu Desnoyers EfficiOS Inc. http://www.efficios.com ___ lttng-dev mailing list lttng-dev@lists.lttng.org https://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev
[lttng-dev] [RELEASE] Babeltrace 2.0.0-rc1
Hi everyone! We're very excited to announce the first Babeltrace 2.0 release candidate! 😃 A prettified version of this announcement is available at: https://diamon.org/babeltrace/docs/release-notes/babeltrace-2.0.0-rc1-release-notes.html What's new since Babeltrace 2.0.0-pre5? === Babeltrace 2.0.0-pre5 was released 3 May 2019. We brought many improvements to the CLI, the project plugins, and the library and its Python bindings. We also updated all the Babeltrace 2 manual pages. The build-time and run-time requirements for Babeltrace 2.0.0-rc1 are updated: * Babeltrace 2.0.0-rc1 does not need the popt library anymore to parse command-line arguments. We wrote our own command-line argument parser to remove this obsolete requirement and to support advanced, position-dependent parsing. * Babeltrace 2.0.0-rc1 requires GLib ≥ 2.28 at build time and run time instead of the previous ≥ 2.22 requirement. Command-line interface -- Automatic source component discovery With the `convert` [1] command's new **automatic source component discovery** feature, specify a path, URI, or arbitrary string to let `babeltrace2` find the most appropriate components to use: $ babeltrace2 /path/to/ctf/trace $ babeltrace2 net://localhost/host/myhost/my-session This means you don't need to create an explicit component with the `--component` [2] option most of the time. Behind the scenes, this feature queries the `babeltrace.support-info` [3] object from all known component classes: a component class can reply with a confidence score to indicate its ability to handle a given path or custom string. For example, a `source.ctf.fs` [4] (CTF trace directory source) component class replies to this query whether or not the given path looks like a CTF trace directory. NOTE: Source component classes do _not_ have to implement the `babeltrace.support-info` query. If a component class does not implement this query, the automatic source component discovery algorithm won't consider it. In that case, you must instantiate such a component class explicitly with the `--component` option. Plugins --- New `sink.text.details` component class ~~~ This new component [5] pretty-prints all the details of the messages it consumes. The output is optimized to be human-readable, yet it is deterministic for testing and debugging purposes. You can use a `sink.text.details` component to easily inspect messages flowing at any point of a graph and make it easy to test and troubleshoot other component classes. The Babeltrace 2 project uses this component class for many tests. `source.ctf.fs` ~~~ A `source.ctf.fs` [4] component can now open and read malformed CTF traces produced by tracers having known bugs and corner cases (LTTng-UST [6], LTTng-modules, and barectf [7]). For example, a `source.ctf.fs` component can now read data streams which the `lttng-crash` [8] tool generates, even if the last packets can be malformed. See the "Trace quirks" [9] section of the `babeltrace2-source.ctf.fs(7)` manual page for more details. Library and Python bindings --- Library-specific: simple sink component ~~~ Add a sink component to a graph easily using the new **simple sink component** C API. A simple sink component is a sink component with a single input port and a single message iterator. This interface reduces the amount of code you need to write to create a basic Babeltrace 2 message consumer. Just provide a consumption user function which receives the component's message iterator to consume upstream messages. You can also implement other user functions: Initialization function: Called once during the initialization phase of the graph. Finalization function: Called once during the finalization phase of the graph. Python-specific: automatic source component discovery using ~~~ `bt2.TraceCollectionMessageIterator` Integrate the same **automatic source component discovery** mechanism which the `babeltrace2` CLI's `convert` [1] command uses to a Python application using a `bt2.TraceCollectionMessageIterator` object. With a `bt2.TraceCollectionMessageIterator` object, your application can access additional component classes installed on the system from the get go. New field class types ~ New field classes are available in libbabeltrace2 and its Python bindings to support eventual, new CTF 2 field classes. The new fields are: Boolean: Contains a boolean value. Bit array: Contains a fixed-size array of bits. A bit array field can represent a CPU status or flag register value, for example. Unlike integer fields, a bit array field is _not_ a numerical field. Option: Contains an optional f
[lttng-dev] [RELEASE] LTTng 2.11.0 - Lafontaine (Linux kernel and user-space tracer)
Hi, This is a combined release announcement for the 2.11.0 - "Lafontaine" release of the LTTng Tools, LTTng UST, and LTTng modules projects. This release is named after a modern Saison beer from Montréal's Oshlag microbrewery. It is a refreshing, zesty, rice beer with hints of fruit and spices. Some even say it makes for a great Somaek when mixed with Chamisul Soju, not that we've tried! Lafontaine is also a tongue-in-cheek reference to a water leak that affected EfficiOS's offices during the development of this release. The most notable features of this new release are: - Session rotation, - Dynamic tracing of user-space (LTTng-modules), - Support for arrays and bitwise binary operators in filters, - User and kernel space call stack capture from the LTTng-modules kernel tracer (LTTng-modules), - Improved networking performance of the relay daemon, - Take NUMA configuration into account for UST buffer allocation (LTTng-UST), - Support unloading of probe providers (dlclose) (LTTng-UST). Important point: since we needed to change the layout of the LTTng-UST shared buffers in this release, we had to bump the ABI major version between LTTng-UST and lttng-sessiond from 7 to 8. Therefore, if incompatible lttng-ust and lttng-sessiond attempt to interact, lttng-ust will not perform any tracing. Make sure you upgrade both lttng-tools and lttng-ust. This release has been brewing for two years. Indeed, LTTng 2.10.0 was released in August 2017, a little more than two years ago. This means we even had the chance to publish talks and material presenting the features introduced in this release already. [1, 2, 3, 4, 5] Read on for a short description of each of these features. -- Session rotation -- The biggest feature of this release is the long-awaited session rotation support. Session rotations now allow you to rotate an ongoing tracing session much in the same way as you would rotate logs. The 'lttng rotate' command rotates the current trace chunk of the current tracing session. Once a rotation is completed, LTTng does not manage the trace chunk archive anymore: you can read it, modify it, move it, or remove it. Because a rotation causes the tracing session’s current sub-buffers to be flushed, trace chunk archives are never redundant, that is, they do not overlap over time, unlike snapshots. Once a rotation is complete, offline analyses can be performed on the resulting trace, much like in 'normal' mode. However, the big advantage is that this can be done without interrupting tracing, and without being limited to tools which implement the "live" protocol. Moreover, session rotations can be scheduled on a time or size basis. The following commands give an idea of how this functionality can be used: $ lttng enable-rotation --timer 30s A rotation schedule is set so that an automatic rotation occurs at least every 30 seconds. $ lttng enable-rotation --size 100M A the rotation schedule is set so that an automatic rotation occurs every time the total size of the flushed part of the current trace chunk is at least 100 MiB. Conversely, session rotation schedules can be deactivated using the 'lttng disable-rotation' command. Finally, it is also possible to use the Notification API to notify external tools when a rotation has been completed. This allows arbitrary actions to be taken on a trace chunk archive when a scheduled rotation is completed. Such actions can include compressing, analyzing, or transferring a trace chunk, for example. -- Dynamic tracing of user-space -- This release also marks the introduction of another feature we have been eager to introduce for a long time: dynamic tracing. As of this release, it is possible to dynamically instrument function entries of applications and shared libraries, as well as DTrace-style SDT probes. The feature relies on the Linux kernel's uprobe facilities. As such, the kernel tracer is needed to benefit from this functionality. Here is an example instrumenting the libc's 'malloc' function which will produce an event named 'libc_malloc' on every invocation of malloc() by any application linked on libc: $ lttng enable-event --kernel \ --userspace-probe /usr/lib/libc-2.28.so:malloc \ libc_malloc SDT probes are tracepoints distributed in multiple libraries and applications. This implementation supports tracing of SDT probes that are NOT guarded by a semaphore. The syntax to enable an SDT tracepoint userspace probe follows: $ lttng enable-event --kernel \ --userspace-probe=sdt:/path/to/executable:provider:probe Note that, for the time being, no payload is extracted (function arguments or SDT probe parameters). -- User and kernel space call stack capture from the LTTng-modules kernel tracer -- Two new contexts have been introduced for kernel channels: callstack-kernel and callstack-user. This allows the sampling of both the kernel and user space call stacks when a k
