README

   1 LTTNG USERSPACE TRACER (LTTng-UST)
   2 ----------------------------
   3
   4 UST web site: http://lttng.org/lttng2.0
   5
   6 Updated versions of this package may be found at:
   7
   8   * Website:  http://lttng.org/lttng2.0
   9   * Releases: http://lttng.org/files/lttng-ust
  10   * GitWeb:   http://git.lttng.org (project: lttng-ust)
  11   * Git:      git://git.lttng.org/lttng-ust.git
  12
  13
  14 PREREQUISITES:
  15
  16   - liburcu
  17     Userspace RCU library, by Mathieu Desnoyers and Paul E. McKenney
  18
  19     -> This release depends on liburcu v0.7.2
  20
  21       * Debian/Ubuntu package: liburcu-dev
  22       * Website:  http://lttng.org/urcu
  23       * Releases: http://lttng.org/files/urcu
  24       * GitWeb:   http://lttng.org/cgi-bin/gitweb.cgi?p=userspace-rcu.git;a=summary
  25       * Git:      git://lttng.org/userspace-rcu.git
  26
  27 For developers using the git tree:
  28
  29 This source tree is based on the autotools suite from GNU to simplify
  30 portability. Here are some things you should have on your system in order to
  31 compile the git repository tree :
  32
  33 - GNU autotools (automake >=1.10, autoconf >=2.50, autoheader >=2.50)
  34   (make sure your system wide "automake" points to a recent version!)
  35 - GNU Libtool >=2.2
  36   (for more information, go to http://www.gnu.org/software/autoconf/)
  37 - Perl (optional)
  38   Needed for make check and tests.
  39
  40 If you get the tree from the repository, you will need to use the "bootstrap"
  41 script in the root of the tree. It calls all the GNU tools needed to prepare the
  42 tree configuration.
  43
  44
  45 INSTALLATION INSTRUCTIONS:
  46
  47   - Download, compile and install liburcu.
  48   - In this package's tree, run ./configure.
  49   - Run make.
  50   - Run make install.
  51   - Run ldconfig.
  52
  53   If compiling from the git repository, run ./bootstrap before running
  54   the configure script, to generate it.
  55
  56
  57 USAGE:
  58
  59   - Create an instrumentation header following the tracepoint examples.
  60     See lttng/tracepoint.h, and examples.
  61
  62   There are 2 ways to compile the Tracepoint Provider with the
  63   application: either statically or dynamically. Please follow
  64   carefully:
  65
  66   1.1) Compile the Tracepoint provider with the application, either
  67        directly or through a static library (.a):
  68     - Into exactly one object of your application: define
  69       "TRACEPOINT_DEFINE" and include the tracepoint provider.
  70     - Use "-I." for the compilation unit containing the tracepoint
  71       provider include (e.g. tp.c).
  72     - Link application with "-ldl" on Linux, with "-lc" on BSD.
  73     - If building the provider directly into the application,
  74       link the application with "-llttng-ust".
  75     - If building a static library for the provider, link the static
  76       library with "-lllttng-ust".
  77     - Include the tracepoint provider header into all C files using
  78       the provider.
  79     - Example:
  80       - tests/hello/  hello.c tp.c ust_tests_hello.h Makefile.example.*
  81
  82   2) Compile the Tracepoint Provider separately from the application,
  83      using dynamic linking:
  84     - Into exactly one object of your application: define
  85       "TRACEPOINT_DEFINE" _and_ also define
  86       "TRACEPOINT_PROBE_DYNAMIC_LINKAGE", then include the tracepoint
  87       provider header.
  88     - Include the tracepoint provider header into all instrumented C
  89       files that use the provider.
  90     - Compile the tracepoint provider with "-I.".
  91     - Link the tracepoint provider with "-llttng-ust".
  92     - Link application with "-ldl" on Linux, "-lc" on BSD.
  93     - Set a LD_PRELOAD environment to preload the tracepoint provider
  94       shared object before starting the application when tracing is
  95       needed. Another way is to dlopen the tracepoint probe when needed
  96       by the application.
  97     - Example:
  98       - tests/demo/   demo.c  tp*.c ust_tests_demo*.h demo-trace
  99
 100   - Enable instrumentation and control tracing with the "lttng" command
 101     from lttng-tools. See lttng-tools doc/quickstart.txt.
 102   - Note about dlclose() usage: it is not safe to use dlclose on a
 103     provider shared object that is being actively used for tracing due
 104     to a lack of reference counting from lttng-ust to the used shared
 105     object.
 106
 107 ENVIRONMENT VARIABLES:
 108
 109   - liblttng-ust debug can be activated by setting the environment variable
 110     "LTTNG_UST_DEBUG" when launching the application. It can also be enabled
 111     at compile-time by compiling libust with -DLTTNG_UST_DEBUG.
 112
 113   - The environment variable "LTTNG_UST_REGISTER_TIMEOUT" can be used to
 114     specify how long the applications should wait for sessiond
 115     "registration done" command before proceeding to execute the main
 116     program. The default is 3000ms (3 seconds). The timeout value is
 117     specified in milliseconds. The value 0 means "don't wait". The value
 118     -1 means "wait forever". Setting this environment variable to 0 is
 119     recommended for applications with time constraints on the process
 120     startup time.
 121
 122   - The compilation flag "-DLTTNG_UST_DEBUG_VALGRIND" should be enabled
 123     at build time to allow liblttng-ust to be used with valgrind
 124     (side-effect: disables per-cpu buffering).
 125
 126
 127 TRACE VIEWER:
 128
 129   Use babeltrace for viewing traces generated by LTTng UST 2.0.
 130   See http://lttng.org for download.
 131
 132
 133 CONTACT:
 134
 135   Maintainer: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
 136   Mailing list: lttng-dev@lists.lttng.org
 137
 138
 139 PACKAGE CONTENTS:
 140
 141   This package contains the following elements.
 142
 143   - liblttng-ust
 144     The actual userspace tracing library that must be linked to the
 145     instrumented programs.
 146
 147   - include
 148     The public header files that will be installed on the system.
 149
 150   - tests
 151     Various test programs
 152
 153   - liblttng-ust-libc-wrapper
 154     An example library that can be LD_PRELOAD'ed to instrument some
 155     calls to libc (currently malloc() and free()) in any program without
 156     need to recompile it.
 157
 158   - liblttng-ust-fork
 159     A library that is LD_PRELOAD'ed, and that hijacks calls to several system
 160     calls in order to trace across these calls. It _has_ to be LD_PRELOAD'ed
 161     in order to hijack calls. In contrast, libust may be linked at build time.
 162
 163   - liblttng-ust-ctl
 164     A library to control tracing in other processes. Used by lttng-tools.
 165
 166   - liblttng-ust-comm
 167     A static library shared between libust and lttng-tools, that
 168     provides functions that allow these components to communicate together.
 169
 170   - libringbuffer
 171     The ring buffer implementation used within LTTng-UST.
 172
 173   - snprintf
 174     An asynchronous signal-safe version of snprintf.
 175
 176   - liblttng-ust-java
 177     A simple library that uses JNI to allow tracing in java programs.
 178     See liblttng-ust-java/README for build instructions.