Linux Trace Toolkit Quickstart
------------------------------
Author : Mathieu Desnoyers, September 2005
-Last update : July 31, 2008
+Last update : January 9th, 2009
This document is made of four parts : the first one explains how to install
What you will typically want is to read sections 2 and 3 : install LTTng from
sources and use it.
-These operations are made for installing the LTTng 0.12 tracer on a linux 2.6.X
-kernel. You will also find instructions for installation of LTTV 0.8.x : the
+These operations are made for installing the LTTng 0.74 tracer on a linux 2.6.X
+kernel. You will also find instructions for installation of LTTV 0.12.x : the
Linux Trace Toolkit Viewer.
To see the list of compatibilities between LTTng, ltt-control, LTTV and
(Debian : libc6, libc6-dev)
(Fedora : glibc, glibc)
+* Reminder
+
+See the list of compatibilities between LTTng, ltt-control, LTTV and
+markers-userspace at :
+http://ltt.polymtl.ca > LTTng+LTTV versions compatibility
+
+
* Getting the LTTng packages
Items preceded by [ ] means they should be removed.
go to the "General setup" section
Select the following options :
- [*] Activate tracepoints
+ [*] Prompt for development and/or incomplete code/drivers
[*] Activate markers
- [*] Activate userspace markers ABI
- <*> Compile generic tracing probes
- Linux Trace Toolkit --->
- [LTTng fine-grained-timestamping]
- [*] Linux Trace Toolkit Instrumentation Support
- <M> or <*> Linux Trace Toolkit Relay+DebugFS Support
+ [*] Activate userspace markers ABI (experimental, optional)
+ [*] Immediate value optimization (optional)
+ [*] Linux Trace Toolkit Next Generation (LTTng) --->
+ <M> or <*> Compile lttng tracing probes
+ <M> or <*> Linux Trace Toolkit High-speed Lockless Data Relay
+ <M> or <*> Linux Trace Toolkit Lock-Protected Data Relay
<M> or <*> Linux Trace Toolkit Serializer
- <M> or <*> Linux Trace Toolkit Marker Control
- <M> or <*> Linux Trace Toolkit Tracer
- It makes no difference for the rest of the procedure whether the Tracer
- is compiled built-in or as a module.
- activate :
- [*] Align Linux Trace Toolkit Traces
- <M> Linux Trace Toolkit Netlink Controller
- <M> Linux Trace Toolkit State Dump
- your choice (see < Help >) :
- [ ] Write heartbeat event to shrink traces
- [ ] Support trace extraction from crash dump
+ <M> or <*> Linux Trace Toolkit Marker Control
+ <M> or <*> Linux Trace Toolkit Tracer
+ [*] Align Linux Trace Toolkit Traces
+ <M> or <*> Support logging events from userspace
+ [*] Support trace extraction from crash dump
+ <M> or <*> Linux Trace Toolkit Trace Controller
+ <M> or <*> Linux Trace Toolkit State Dump
Select <Exit>
Select <Exit>
Select <Yes>
-- on X86, X86_64
make install
reboot
-Select the Linux 2.6.17-lttng-0.x.xx kernel in your boot loader.
+Select the Linux 2.6.X-lttng-0.x.xx kernel in your boot loader.
-- on PowerPC
cp vmlinux.strip /boot/vmlinux-2.6.X-lttng-0.x.xx
ybin
select the right entry at the yaboot prompt (see choices : tab, select : type
the kernel name followed by enter)
-Select the Linux 2.6.17-lttng-0.x.xx kernel in your boot loader.
+Select the Linux 2.6.X-lttng-0.x.xx kernel in your boot loader.
--
these commands load all LTT modules. Depending on what options you chose to
compile statically, you may not need to issue all these commands.
-modprobe ltt-control
+modprobe ltt-trace-control
modprobe ltt-marker-control
modprobe ltt-tracer
modprobe ltt-serialize
modprobe mm-trace
modprobe net-trace
modprobe fs-trace
+modprobe jbd2-trace
+modprobe ext4-trace
modprobe syscall-trace
+modprobe trap-trace
#if locking tracing is wanted, uncomment the following
#modprobe lockdep-trace
You can automate at boot time loading the ltt-control module by :
cp /etc/modules /etc/modules.bkp
-echo ltt-control >> /etc/modules
+echo ltt-trace-control >> /etc/modules
echo ltt-marker-control >> /etc/modules
echo ltt-tracer >> /etc/modules
echo ltt-serialize >> /etc/modules
echo mm-trace >> /etc/modules
echo net-trace >> /etc/modules
echo fs-trace >> /etc/modules
+echo jbd2-trace >> /etc/modules
+echo ext4-trace >> /etc/modules
+echo syscall-trace >> /etc/modules
+echo trap-trace >> /etc/modules
#if locking tracing is wanted, uncomment the following
#echo lockdep-trace >> /etc/modules
su -
cd /usr/src
wget http://ltt.polymtl.ca/lttng/ltt-control-0.x-xxxx2006.tar.gz
-gzip -cd ltt-control-0.x-xxxx2006.tar.gz | tar xvof -
+gzip -cd ltt-control-0.x-xxxx2008.tar.gz | tar xvof -
cd ltt-control-0.x-xxxx2006
(refer to README to see the development libraries that must be installed on you
system)
make
make install
-* Getting and installing the markers-userspace package for user space tracing
-See http://ltt.polymtl.ca/packages/markers-userspace-0.5.tar.bz2 or more recent.
+
+* Userspace tracing
+
+Make sure you selected the kernel menuconfig option :
+ <M> or <*> Support logging events from userspace
+And that the ltt-userspace-event kernel module is loaded if selected as a
+module.
+
+Simple userspace tracing is available through
+echo "some text to record" > /mnt/debugfs/ltt/write_event
+
+It will appear in the trace under event :
+channel : userspace
+event name : event
* Getting and installing the LTTV package (on the visualisation machine, same or
make install
+* Getting and installing the markers-userspace package for user space tracing
+(experimental)
+See http://ltt.polymtl.ca/packages/markers-userspace-0.5.tar.bz2 or more recent.
+
***********************************************************
Start tracing :
-lttctl -n trace -d -l /mnt/debugfs/ltt -t /tmp/trace
+lttctl -C -w /tmp/trace1 trace1
Stop tracing and destroy trace channels :
-lttctl -n trace -R
+lttctl -D trace1
see lttctl --help for details.
(note : to see if the buffers has been filled, look at the dmesg output after
lttctl -R or after stopping tracing from the GUI, it will show an event lost
count. If it is the case, try using larger buffers. See lttctl --help to learn
-how.)
+how. lttv now also shows event lost messages in the console when loading a trace
+with missing events or lost subbuffers.)
* Use text mode LTTV
The following lttctl commands take an hybrid trace :
Create trace channel, start lttd on normal channels, start tracing:
-lttctl -n tracename -d -l /mnt/debugfs/ltt -t /tmp/trace1 -m hybrid
+lttctl -C -w /tmp/trace2 -o channel.kernel.overwrite=1 trace2
Stop tracing, start lttd on flight recorder channels, destroy trace channels :
-lttctl -n tracename -f -l /mnt/debugfs/ltt -t /tmp/trace1 -m hybrid
-
+lttctl -D -w /tmp/trace2 trace2
-We will need to tweak what we consider "important" medium rate events. For
-instance, thread branding events are actually considered a "high rate" event
-when it should be considered "medium rate". The same should apply for the
-state dump process enumeration.
+Each "overwrite" channel is flight recorder channel.
* Flight recorder mode
The flight recorder mode writes data into overwritten buffers for all channels,
-including control channels, except for the facilities tracefiles.
+including control channels, except for the facilities tracefiles. It consists of
+setting all channels to "overwrite".
The following lttctl commands take a flight recorder trace :
-lttctl -n trace -c -m flight
-lttd -n -d -t /tmp/trace -c /mnt/debugfs/ltt/trace
-lttctl -n trace -s
-.. do stuff
-lttctl -n trace -q
-lttd -f -d -t /tmp/trace -c /mnt/debugfs/ltt/trace
-lttctl -m trace -r
+lttctl -C -w /tmp/trace3 -o channel.all.overwrite=1 trace3
+...
+lttctl -D -w /tmp/trace3 trace3
**************************************************************