README

   1 LTTNG USERSPACE TRACER (LTTng-UST)
   2 ----------------------------
   3
   4 UST web site: http://lttng.org
   5
   6 Updated versions of this package may be found at:
   7
   8   * Releases: http://lttng.org/download
   9   * GitWeb:   http://git.lttng.org (project: lttng-ust)
  10   * Git:      git://git.lttng.org/lttng-ust.git
  11
  12
  13 PREREQUISITES:
  14
  15   - liburcu
  16     Userspace RCU library, by Mathieu Desnoyers and Paul E. McKenney
  17
  18     -> This release depends on liburcu v0.7.2
  19
  20       * Debian/Ubuntu package: liburcu-dev
  21       * Website:  http://lttng.org/urcu
  22       * Releases: http://lttng.org/files/urcu
  23       * GitWeb:   http://lttng.org/cgi-bin/gitweb.cgi?p=userspace-rcu.git;a=summary
  24       * Git:      git://lttng.org/userspace-rcu.git
  25
  26 For developers using the git tree:
  27
  28 This source tree is based on the autotools suite from GNU to simplify
  29 portability. Here are some things you should have on your system in order to
  30 compile the git repository tree :
  31
  32 - GNU autotools (automake >=1.10, autoconf >=2.50, autoheader >=2.50)
  33   (make sure your system wide "automake" points to a recent version!)
  34 - GNU Libtool >=2.2
  35   (for more information, go to http://www.gnu.org/software/autoconf/)
  36 - Perl (optional)
  37   Needed for make check and tests.
  38
  39 If you get the tree from the repository, you will need to use the "bootstrap"
  40 script in the root of the tree. It calls all the GNU tools needed to prepare the
  41 tree configuration.
  42
  43
  44 INSTALLATION INSTRUCTIONS:
  45
  46   - Download, compile and install liburcu.
  47   - In this package's tree, run ./configure.
  48   - Run make.
  49   - Run make install.
  50   - Run ldconfig.
  51
  52   If compiling from the git repository, run ./bootstrap before running
  53   the configure script, to generate it.
  54
  55
  56 USAGE:
  57
  58   - Create an instrumentation header following the tracepoint examples.
  59     See lttng/tracepoint.h, and examples.
  60
  61   There are 2 ways to compile the Tracepoint Provider with the
  62   application: either statically or dynamically. Please follow
  63   carefully:
  64
  65   1.1) Compile the Tracepoint provider with the application, either
  66        directly or through a static library (.a):
  67     - Into exactly one object of your application: define
  68       "TRACEPOINT_DEFINE" and include the tracepoint provider.
  69     - Use "-I." for the compilation unit containing the tracepoint
  70       provider include (e.g. tp.c).
  71     - Link application with "-ldl" on Linux, with "-lc" on BSD.
  72     - If building the provider directly into the application,
  73       link the application with "-llttng-ust".
  74     - If building a static library for the provider, link the static
  75       library with "-llttng-ust".
  76     - Include the tracepoint provider header into all C files using
  77       the provider.
  78     - Example:
  79       - tests/hello/  hello.c tp.c ust_tests_hello.h Makefile.example.*
  80
  81   2) Compile the Tracepoint Provider separately from the application,
  82      using dynamic linking:
  83     - Into exactly one object of your application: define
  84       "TRACEPOINT_DEFINE" _and_ also define
  85       "TRACEPOINT_PROBE_DYNAMIC_LINKAGE", then include the tracepoint
  86       provider header.
  87     - Include the tracepoint provider header into all instrumented C
  88       files that use the provider.
  89     - Compile the tracepoint provider with "-I.".
  90     - Link the tracepoint provider with "-llttng-ust".
  91     - Link application with "-ldl" on Linux, "-lc" on BSD.
  92     - Set a LD_PRELOAD environment to preload the tracepoint provider
  93       shared object before starting the application when tracing is
  94       needed. Another way is to dlopen the tracepoint probe when needed
  95       by the application.
  96     - Example:
  97       - tests/demo/   demo.c  tp*.c ust_tests_demo*.h demo-trace
  98
  99   - Enable instrumentation and control tracing with the "lttng" command
 100     from lttng-tools. See lttng-tools doc/quickstart.txt.
 101   - Note about dlclose() usage: it is not safe to use dlclose on a
 102     provider shared object that is being actively used for tracing due
 103     to a lack of reference counting from lttng-ust to the used shared
 104     object.
 105
 106 ENVIRONMENT VARIABLES:
 107
 108   - liblttng-ust debug can be activated by setting the environment variable
 109     "LTTNG_UST_DEBUG" when launching the application. It can also be enabled
 110     at compile-time by compiling libust with -DLTTNG_UST_DEBUG.
 111
 112   - The environment variable "LTTNG_UST_REGISTER_TIMEOUT" can be used to
 113     specify how long the applications should wait for sessiond
 114     "registration done" command before proceeding to execute the main
 115     program. The default is 3000ms (3 seconds). The timeout value is
 116     specified in milliseconds. The value 0 means "don't wait". The value
 117     -1 means "wait forever". Setting this environment variable to 0 is
 118     recommended for applications with time constraints on the process
 119     startup time.
 120
 121   - The compilation flag "-DLTTNG_UST_DEBUG_VALGRIND" should be enabled
 122     at build time to allow liblttng-ust to be used with valgrind
 123     (side-effect: disables per-cpu buffering).
 124
 125
 126 TRACE VIEWER:
 127
 128   Use babeltrace for viewing traces generated by LTTng UST 2.x.
 129   See http://lttng.org for download.
 130
 131
 132 CONTACT:
 133
 134   Maintainer: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
 135   Mailing list: lttng-dev@lists.lttng.org
 136
 137
 138 PACKAGE CONTENTS:
 139
 140   This package contains the following elements.
 141
 142   - liblttng-ust
 143     The actual userspace tracing library that must be linked to the
 144     instrumented programs.
 145
 146   - include
 147     The public header files that will be installed on the system.
 148
 149   - tests
 150     Various test programs
 151
 152   - liblttng-ust-libc-wrapper
 153     An example library that can be LD_PRELOAD'ed to instrument some
 154     calls to libc (currently malloc() and free()) in any program without
 155     need to recompile it.
 156
 157   - liblttng-ust-fork
 158     A library that is LD_PRELOAD'ed, and that hijacks calls to several system
 159     calls in order to trace across these calls. It _has_ to be LD_PRELOAD'ed
 160     in order to hijack calls. In contrast, libust may be linked at build time.
 161
 162   - liblttng-ust-ctl
 163     A library to control tracing in other processes. Used by lttng-tools.
 164
 165   - liblttng-ust-comm
 166     A static library shared between libust and lttng-tools, that
 167     provides functions that allow these components to communicate together.
 168
 169   - libringbuffer
 170     The ring buffer implementation used within LTTng-UST.
 171
 172   - snprintf
 173     An asynchronous signal-safe version of snprintf.
 174
 175   - liblttng-ust-java
 176     A simple library that uses JNI to allow tracing in java programs.
 177     See liblttng-ust-java/README for build instructions.