X-Git-Url: http://git.liburcu.org/?a=blobdiff_plain;f=2.10%2Flttng-docs-2.10.txt;h=375fcf5cf4d716cae7c746e04ca242b8335203be;hb=fc360555a06a69e32835d6fbc03d41594ebd0637;hp=defbdf687057eee30c05bca0c519ccaa4d1665ba;hpb=b0e4019318ed6e99056bf0540d9b5262ebcf5d66;p=lttng-docs.git diff --git a/2.10/lttng-docs-2.10.txt b/2.10/lttng-docs-2.10.txt index defbdf6..375fcf5 100644 --- a/2.10/lttng-docs-2.10.txt +++ b/2.10/lttng-docs-2.10.txt @@ -1,12 +1,15 @@ The LTTng Documentation ======================= Philippe Proulx -v2.10, 3 October 2017 +v2.10, 25 February 2021 include::../common/copyright.txt[] +include::../common/warning-not-maintained.txt[] + + include::../common/welcome.txt[] @@ -297,6 +300,8 @@ becomes inactive or in real-time. [[installing-lttng]] == Installation +include::../common/warning-no-installation.txt[] + **LTTng** is a set of software <> which interact to <> the Linux kernel and user applications, and to <> (start and stop @@ -311,259 +316,14 @@ components are bundled into the following packages: trace user applications. Most distributions mark the LTTng-modules and LTTng-UST packages as -optional when installing LTTng-tools (which is always required). In the -following sections, we always provide the steps to install all three, -but note that: +optional when installing LTTng-tools (which is always required). Note +that: * You only need to install LTTng-modules if you intend to trace the Linux kernel. * You only need to install LTTng-UST if you intend to trace user applications. -[role="growable"] -.Availability of LTTng{nbsp}{revision} for major Linux distributions as of 3 October 2017. -|==== -|Distribution |Available in releases |Alternatives - -|https://www.ubuntu.com/[Ubuntu] -|Ubuntu{nbsp}14.04 _Trusty Tahr_ and Ubuntu{nbsp}16.04 _Xenial Xerus_: -<>. -|link:/docs/v2.9#doc-ubuntu[LTTng{nbsp}2.9 for Ubuntu{nbsp}17.04 _Zesty Zapus_ and Ubuntu{nbsp}17.10 _Artful Aardvark_]. - -<> for -other Ubuntu releases. - -|https://getfedora.org/[Fedora] -|<>. -|link:/docs/v2.9#doc-fedora[LTTng{nbsp}2.9 for Fedora 26]. - -<> for -other Fedora releases. - -|https://www.debian.org/[Debian] -|<>. -|link:/docs/v2.9#doc-debian[LTTng{nbsp}2.9 for Debian "stretch" (stable)]. - -<>. - -|https://www.archlinux.org/[Arch Linux] -|<>. -|<>. - -|https://alpinelinux.org/[Alpine Linux] -|_Not available_ -|link:/docs/v2.9#doc-alpine-linux[LTTng{nbsp}2.9 for Alpine Linux "edge"]. - -<>. - -|https://www.redhat.com/[RHEL] and https://www.suse.com/[SLES] -|See http://packages.efficios.com/[EfficiOS Enterprise Packages]. -| - -|https://buildroot.org/[Buildroot] -|_Not available_ -|link:/docs/v2.9#doc-buildroot[LTTng{nbsp}2.9 for Buildroot{nbsp}2017.02 and -Buildroot{nbsp}2017.05]. - -<>. - -|http://www.openembedded.org/wiki/Main_Page[OpenEmbedded] and -https://www.yoctoproject.org/[Yocto] -|_Not available_ -|link:/docs/v2.9#doc-oe-yocto[LTTng{nbsp}2.9 for Yocto Project{nbsp}2.3 _Pyro_] -(`openembedded-core` layer). - -<>. -|==== - - -[[ubuntu]] -=== [[ubuntu-official-repositories]]Ubuntu - -[[ubuntu-ppa]] -==== noch:{LTTng} Stable {revision} PPA - -The https://launchpad.net/~lttng/+archive/ubuntu/stable-{revision}[LTTng -Stable{nbsp}{revision} PPA] offers the latest stable -LTTng{nbsp}{revision} packages for: - -* Ubuntu{nbsp}14.04 _Trusty Tahr_ -* Ubuntu{nbsp}16.04 _Xenial Xerus_ - -To install LTTng{nbsp}{revision} from the LTTng Stable{nbsp}{revision} PPA: - -. Add the LTTng Stable{nbsp}{revision} PPA repository and update the - list of packages: -+ --- -[role="term"] ----- -# apt-add-repository ppa:lttng/stable-2.10 -# apt-get update ----- --- - -. Install the main LTTng{nbsp}{revision} packages: -+ --- -[role="term"] ----- -# apt-get install lttng-tools -# apt-get install lttng-modules-dkms -# apt-get install liblttng-ust-dev ----- --- - -. **If you need to instrument and trace - <>**, install the LTTng-UST - Java agent: -+ --- -[role="term"] ----- -# apt-get install liblttng-ust-agent-java ----- --- - -. **If you need to instrument and trace - <>**, install the - LTTng-UST Python agent: -+ --- -[role="term"] ----- -# apt-get install python3-lttngust ----- --- - - -[[fedora]] -=== Fedora - -To install LTTng{nbsp}{revision} on Fedora{nbsp}27: - -. Install the LTTng-tools{nbsp}{revision} and LTTng-UST{nbsp}{revision} - packages: -+ --- -[role="term"] ----- -# yum install lttng-tools -# yum install lttng-ust ----- --- - -. Download, build, and install the latest LTTng-modules{nbsp}{revision}: -+ --- -[role="term"] ----- -$ cd $(mktemp -d) && -wget http://lttng.org/files/lttng-modules/lttng-modules-latest-2.10.tar.bz2 && -tar -xf lttng-modules-latest-2.10.tar.bz2 && -cd lttng-modules-2.10.* && -make && -sudo make modules_install && -sudo depmod -a ----- --- - -[IMPORTANT] -.Java and Python application instrumentation and tracing -==== -If you need to instrument and trace <> on Fedora, you need to build and install -LTTng-UST{nbsp}{revision} <> and pass -the `--enable-java-agent-jul`, `--enable-java-agent-log4j`, or -`--enable-java-agent-all` options to the `configure` script, depending -on which Java logging framework you use. - -If you need to instrument and trace <> on Fedora, you need to build and install -LTTng-UST{nbsp}{revision} from source and pass the -`--enable-python-agent` option to the `configure` script. -==== - - -[[debian]] -=== Debian - -To install LTTng{nbsp}{revision} on Debian "buster" (testing) -or Debian "sid" (unstable): - -. Install the main LTTng{nbsp}{revision} packages: -+ --- -[role="term"] ----- -# apt-get install lttng-modules-dkms -# apt-get install liblttng-ust-dev -# apt-get install lttng-tools ----- --- - -. **If you need to instrument and trace <>**, install the LTTng-UST Java agent: -+ --- -[role="term"] ----- -# apt-get install liblttng-ust-agent-java ----- --- - -. **If you need to instrument and trace <>**, install the LTTng-UST Python agent: -+ --- -[role="term"] ----- -# apt-get install python3-lttngust ----- --- - - -[[arch-linux]] -=== Arch Linux - -LTTng-UST{nbsp}{revision} is available in Arch Linux's _Community_ -repository, while LTTng-tools{nbsp}{revision} and -LTTng-modules{nbsp}{revision} are available in the -https://aur.archlinux.org/[AUR]. - -To install LTTng{nbsp}{revision} on Arch Linux, using -https://github.com/rmarquis/pacaur[pacaur] for the AUR packages: - -. Install the main LTTng{nbsp}{revision} packages: -+ --- -[role="term"] ----- -# pacman -Sy lttng-ust -$ pacaur -Sy lttng-tools -$ pacaur -Sy lttng-modules ----- --- - -. **If you need to instrument and trace <>**, install the LTTng-UST Python agent: -+ --- -[role="term"] ----- -# pacman -Sy python-lttngust -# pacman -Sy python2-lttngust ----- --- - - -[[enterprise-distributions]] -=== RHEL, SUSE, and other enterprise distributions - -To install LTTng on enterprise Linux distributions, such as Red Hat -Enterprise Linux (RHEL) and SUSE Linux Enterprise Server (SUSE), please -see http://packages.efficios.com/[EfficiOS Enterprise Packages]. - [[building-from-source]] === Build from source @@ -746,19 +506,23 @@ tracepoints (this will generate a lot of data when tracing): . Do some operation on your system for a few seconds. For example, load a website, or list the files of a directory. -. <> and destroy the +. <> the current tracing session: + -- [role="term"] ---- -# lttng stop # lttng destroy ---- -- + The man:lttng-destroy(1) command does not destroy the trace data; it only destroys the state of the tracing session. ++ +The man:lttng-destroy(1) command also runs the man:lttng-stop(1) command +implicitly (see <>). You need to stop tracing to make LTTng flush the remaining +trace data and make the trace readable. . For the sake of this example, make the recorded trace accessible to the non-root users: @@ -991,19 +755,23 @@ $ lttng start . Go back to the running `hello` application and press Enter. The program executes all `tracepoint()` instrumentation points and exits. -. <> and destroy the +. <> the current tracing session: + -- [role="term"] ---- -$ lttng stop $ lttng destroy ---- -- + The man:lttng-destroy(1) command does not destroy the trace data; it only destroys the state of the tracing session. ++ +The man:lttng-destroy(1) command also runs the man:lttng-stop(1) command +implicitly (see <>). You need to stop tracing to make LTTng flush the remaining +trace data and make the trace readable. By default, LTTng saves the traces in +$LTTNG_HOME/lttng-traces/__name__-__date__-__time__+, @@ -1254,11 +1022,11 @@ LTTng can send the generated trace data to different locations. The _tracing session mode_ dictates where to send it. The following modes are available in LTTng{nbsp}{revision}: -Local mode:: +[[local-mode]]Local mode:: LTTng writes the traces to the file system of the machine being traced (target system). -Network streaming mode:: +[[net-streaming-mode]]Network streaming mode:: LTTng sends the traces over the network to a <> running on a remote system. @@ -1269,7 +1037,7 @@ Snapshot mode:: or to send it over the network to a <> running on a remote system. -Live mode:: +[[live-mode]]Live mode:: This mode is similar to the network streaming mode, but a live trace viewer can connect to the distant relay daemon to <> by @@ -1434,18 +1202,23 @@ discard mode, the tracer only discards the event record that doesn't fit. In discard mode, LTTng increments a count of lost event records when an -event record is lost and saves this count to the trace. In overwrite -mode, since LTTng 2.8, LTTng increments a count of lost sub-buffers when -a sub-buffer is lost and saves this count to the trace. In this mode, -the exact number of lost event records in those lost sub-buffers is not -saved to the trace. Trace analyses can use the trace's saved discarded -event record and sub-buffer counts to decide whether or not to perform -the analyses even if trace data is known to be missing. +event record is lost and saves this count to the trace. Since +LTTng{nbsp}2.8, in overwrite mode, LTTng writes to a given sub-buffer +its sequence number within its data stream. With a <>, +<>, or <> +<>, a trace reader can use such +sequence numbers to report lost packets. In overwrite mode, LTTng +doesn't write to the trace the exact number of lost event records in +those lost sub-buffers. + +Trace analyses can use saved discarded event record and sub-buffer +(packet) counts of the trace to decide whether or not to perform the +analyses even if trace data is known to be missing. There are a few ways to decrease your probability of losing event records. <> shows -how you can fine-une the sub-buffer count and size of a channel to +how you can fine-tune the sub-buffer count and size of a channel to virtually stop losing event records, though at the cost of greater memory usage. @@ -1655,7 +1428,7 @@ The LTTng project incorporates: * **LTTng-tools**: Libraries and command-line interface to control tracing sessions. ** <> (man:lttng-sessiond(8)). -** <> (man:lttng-consumerd(8)). +** <> (cmd:lttng-consumerd). ** <> (man:lttng-relayd(8)). ** <> (`liblttng-ctl`). ** <> (man:lttng(1)). @@ -1951,7 +1724,7 @@ running. You can also start the session daemon manually. .The consumer daemon. image::plumbing-consumerd.png[] -The _consumer daemon_, man:lttng-consumerd(8), is a daemon which shares +The _consumer daemon_, cmd:lttng-consumerd, is a daemon which shares ring buffers with user applications or with the LTTng kernel modules to collect trace data and send it to some location (on disk or to a <> over the network). The consumer daemon @@ -4126,7 +3899,7 @@ $ lttng enable-event --userspace 'lttng_ust_tracelog:*' [[prebuilt-ust-helpers]] === Prebuilt user space tracing helpers -The LTTng-UST package provides a few helpers in the form or preloadable +The LTTng-UST package provides a few helpers in the form of preloadable shared objects which automatically instrument system functions and calls. @@ -4288,7 +4061,7 @@ logging frameworks: .LTTng-UST Java agent imported by a Java application. image::java-app.png[] -Note that the methods described below are new in LTTng{nbsp}{revision}. +Note that the methods described below are new in LTTng{nbsp}2.8. Previous LTTng versions use another technique. NOTE: We use http://openjdk.java.net/[OpenJDK]{nbsp}8 for development @@ -5641,6 +5414,11 @@ $ lttng destroy ---- -- +The man:lttng-destroy(1) command also runs the man:lttng-stop(1) +command implicitly (see <>). You need to stop tracing to make LTTng flush the +remaining trace data and make the trace readable. + [[list-instrumentation-points]] === List the available instrumentation points @@ -5725,8 +5503,9 @@ Tracepoint or system call name. In the case of a Linux KProbe or function, this is a custom name given to the event rule. With the JUL, log4j, and Python domains, this is a logger name. -With a tracepoint, logger, or system call name, the last character -can be `*` to match anything that remains. +With a tracepoint, logger, or system call name, you can use the special +`*` globbing character to match anything (for example, `sched_*`, +`my_comp*:*msg_*`). |All. @@ -5988,6 +5767,12 @@ records>> or lost sub-buffers since the last time you ran man:lttng-start(1), warnings are printed when you run the man:lttng-stop(1) command. +IMPORTANT: You need to stop tracing to make LTTng flush the remaining +trace data and make the trace readable. Note that the +man:lttng-destroy(1) command (see +<>) also runs the man:lttng-stop(1) command implicitly. + [[enabling-disabling-channels]] === Create a channel @@ -6370,8 +6155,8 @@ leads to this whitelist: .PIDs 3, 7, 10, and 13 are removed from the whitelist. image::track-1-4-15-16.png[] -LTTng can track all possible PIDs again using the opt:track(1):--all -option: +LTTng can track all possible PIDs again using the +opt:lttng-track(1):--all option: [role="term"] ----