The LTTng Documentation
=======================
Philippe Proulx <pproulx@efficios.com>
-v2.10, 1 August 2017
+v2.10, 22 January 2018
include::../common/copyright.txt[]
[role="term"]
----
$ lttng create
-$ lttng enable-channel --userspace --blocking-timeout=-1 blocking-channel
+$ lttng enable-channel --userspace --blocking-timeout=inf blocking-channel
$ lttng enable-event --userspace --channel=blocking-channel --all
$ lttng start
$ LTTNG_UST_ALLOW_BLOCKING=1 my-app
applications.
[role="growable"]
-.Availability of LTTng{nbsp}{revision} for major Linux distributions as of 25 July 2017.
+.Availability of LTTng{nbsp}{revision} for major Linux distributions as of 22 January 2018.
|====
|Distribution |Available in releases |Alternatives
|https://www.ubuntu.com/[Ubuntu]
|Ubuntu{nbsp}14.04 _Trusty Tahr_ and Ubuntu{nbsp}16.04 _Xenial Xerus_:
<<ubuntu-ppa,use the LTTng Stable{nbsp}{revision} PPA>>.
-|link:/docs/v2.9#doc-ubuntu[LTTng{nbsp}2.9 for Ubuntu{nbsp}17.04 _Zesty Zapus_].
+|link:/docs/v2.9#doc-ubuntu[LTTng{nbsp}2.9 for Ubuntu{nbsp}17.04 _Zesty Zapus_ and Ubuntu{nbsp}17.10 _Artful Aardvark_].
<<building-from-source,Build LTTng{nbsp}{revision} from source>> for
other Ubuntu releases.
|https://getfedora.org/[Fedora]
-|_Not available_
-|link:/docs/v2.9#doc-fedora[LTTng{nbsp}2.9 for Fedora 26].
+|<<fedora,Fedora{nbsp}27>>.
+|link:/docs/v2.9#doc-fedora[LTTng{nbsp}2.9 for Fedora{nbsp}26].
-<<building-from-source,Build LTTng{nbsp}{revision} from source>>.
+<<building-from-source,Build LTTng{nbsp}{revision} from source>> for
+other Fedora releases.
|https://www.debian.org/[Debian]
-|_Not available_
-|link:/docs/v2.9#doc-debian[LTTng{nbsp}2.9 for Debian "stretch"
-(stable), Debian "buster" (testing), and Debian "sid" (unstable)].
+|<<debian,Debian "buster" (testing) and Debian "sid" (unstable)>>.
+|link:/docs/v2.9#doc-debian[LTTng{nbsp}2.9 for Debian "stretch" (stable)].
<<building-from-source,Build LTTng{nbsp}{revision} from source>>.
|https://www.archlinux.org/[Arch Linux]
-|_Not available_
-|link:/docs/v2.9#doc-arch-linux[LTTng{nbsp}2.9 in the latest AUR packages].
+|<<arch-linux,Current Arch Linux build>>.
+|<<building-from-source,Build LTTng{nbsp}{revision} from source>>.
|https://alpinelinux.org/[Alpine Linux]
-|_Not available_
-|link:/docs/v2.9#doc-alpine-linux[LTTng{nbsp}2.9 for Alpine Linux "edge"].
-
-<<building-from-source,Build LTTng{nbsp}{revision} from source>>.
+|<<alpine-linux,Alpine Linux{nbsp}3.7 and Alpine Linux{nbsp}"edge">>.
+|<<building-from-source,Build LTTng{nbsp}{revision} from source>>.
|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].
+|link:/docs/v2.9#doc-buildroot[LTTng{nbsp}2.9 for Buildroot{nbsp}2017.02,
+Buildroot{nbsp}2017.05, Buildroot{nbsp}2017.08, and Buildroot{nbsp}2017.11].
<<building-from-source,Build LTTng{nbsp}{revision} from source>>.
|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_]
+|link:/docs/v2.9#doc-oe-yocto[LTTng{nbsp}2.9 for Yocto Project{nbsp}2.3 _Pyro_
+and Yocto Project{nbsp}2.4 _Rocko_]
(`openembedded-core` layer).
<<building-from-source,Build LTTng{nbsp}{revision} from source>>.
--
+[[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 <<java-application,Java
+applications>> on Fedora, you need to build and install
+LTTng-UST{nbsp}{revision} <<building-from-source,from source>> 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 <<python-application,Python
+applications>> 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 <<java-application,Java
+ applications>>**, install the LTTng-UST Java agent:
++
+--
+[role="term"]
+----
+# apt-get install liblttng-ust-agent-java
+----
+--
+
+. **If you need to instrument and trace <<python-application,Python
+ applications>>**, 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 <<python-application,Python
+ applications>>**, install the LTTng-UST Python agent:
++
+--
+[role="term"]
+----
+# pacman -Sy python-lttngust
+# pacman -Sy python2-lttngust
+----
+--
+
+
+[[alpine-linux]]
+=== Alpine Linux
+
+To install LTTng-tools{nbsp}{revision} and LTTng-UST{nbsp}{revision} on
+Alpine Linux{nbsp}3.7 or Alpine Linux{nbsp}"edge":
+
+. **If you're installing for Alpine Linux{nbsp}"edge"**, make sure your
+ system is https://wiki.alpinelinux.org/wiki/Edge[configured for
+ "edge"].
+. **If you're installing for Alpine Linux{nbsp}"edge"**, enable the _testing_
+ repository by uncommenting the corresponding line in
+ path:{/etc/apk/repositories}.
+. Add the LTTng packages:
++
+--
+[role="term"]
+----
+# apk add lttng-tools
+# apk add lttng-ust-dev
+----
+--
+
+To install LTTng-modules{nbsp}{revision} (Linux kernel tracing support)
+on Alpine Linux{nbsp}3.7 or Alpine Linux{nbsp}"edge":
+
+. Add the vanilla Linux kernel:
++
+--
+[role="term"]
+----
+# apk add linux-vanilla linux-vanilla-dev
+----
+--
+
+. Reboot with the vanilla Linux kernel.
+. 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
+----
+--
+
+
[[enterprise-distributions]]
=== RHEL, SUSE, and other enterprise distributions
Which mechanism you should choose depends on your context: prioritize
the newest or the oldest event records in the ring buffer?
-Beware that, in overwrite mode, the tracer abandons a whole sub-buffer
+Beware that, in overwrite mode, the tracer abandons a _whole sub-buffer_
as soon as a there's no space left for a new event record, whereas in
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, LTTng keeps no information when it overwrites a
-sub-buffer before consuming it.
+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.
There are a few ways to decrease your probability of losing event
records.
0 (default)::
Never block (non-blocking mode).
--1::
+`inf`::
Block forever until space is available in a sub-buffer to record
the event.
[role="term"]
----
$ lttng create
-$ lttng enable-channel --userspace --blocking-timeout=-1 blocking-channel
+$ lttng enable-channel --userspace --blocking-timeout=inf blocking-channel
$ lttng enable-event --userspace --channel=blocking-channel --all
$ lttng start
----
projects / lttng-docs.git / blobdiff