On Tue, Jun 12, 2018 at 11:15 AM, Vidushi Vashishth <reachv...@gmail.com> wrote: > > Adjusted line length to 79-80 > --- > user/index.rst | 2 + > user/tracing/captureengine.rst | 188 ++++++++++++++++++++++++++ > user/tracing/examples.rst | 12 ++ > user/tracing/index.rst | 33 +++++ > user/tracing/introduction.rst | 184 ++++++++++++++++++++++++++ > user/tracing/tracelinker.rst | 294 > +++++++++++++++++++++++++++++++++++++++++ > user/tracing/usecases.rst | 129 ++++++++++++++++++ > 7 files changed, 842 insertions(+) > create mode 100644 user/tracing/captureengine.rst > create mode 100644 user/tracing/examples.rst > create mode 100644 user/tracing/index.rst > create mode 100644 user/tracing/introduction.rst > create mode 100644 user/tracing/tracelinker.rst > create mode 100644 user/tracing/usecases.rst > > diff --git a/user/index.rst b/user/index.rst > index 8cbcd1b..a764fe8 100644 > --- a/user/index.rst > +++ b/user/index.rst > @@ -52,6 +52,8 @@ to the Community Project hosted at http://www.rtems.org/. > > tools/index > > + tracing/index > + > support/index > > glossary/index > diff --git a/user/tracing/captureengine.rst b/user/tracing/captureengine.rst > new file mode 100644 > index 0000000..b80d7d0 > --- /dev/null > +++ b/user/tracing/captureengine.rst > @@ -0,0 +1,188 @@ > +.. comment SPDX-License-Identifier: CC-BY-SA-4.0 > + > +.. comment: Copyright (c) 2016 Chris Johns <chr...@rtems.org> > +.. comment: All rights reserved. > + > +.. _capturengine: > + > +Capture Engine > +************** > + > +Capture Engine is a trace tool built inside the RTEMS operating system. > Capture > +Engine
It is not right to just blanket wrap to 80 characters. This one word on a line by itself is no good. Many text editors can make the wrapping work in a nice way, but I don't know what editor you use. For example, I use vim, and text formatting can be done by highlighting text in Visual mode and using 'gq' command to reformat. > +is designed to cause the lowest load on the system when operating. Hence it > +does not > +effect RTEMS when operating or when disabled. It binds to RTEMS at runtime > and > +does not > +require RTEMS or your application to be rebuilt in order to use it. > + > +The Capture Engine's sample testcase for the `sparc/erc32` is available in > the > +"$HOME/development/rtems/kernel/erc32/sparc-rtems5/c/erc32/testsuites/samples" > +directory, > +provided you followed the installation directions of the quickstart section. > In > +order to > +access the capture testcase perform the following set of operations. > + > +.. code-block:: shell > + > + $ cd > + > $HOME/development/rtems/kernel/erc32/sparc-rtems5/c/erc32/testsuites/samples > + $ ../samples > + $ sparc-rtems5-run ./capture.exe > + > + > + *** BEGIN OF TEST CAPTURE ENGINE *** > + *** TEST VERSION: 5.0.0.de9b7d712bf5da6593386fd4fbca0d5f8b8431d8 > + *** TEST STATE: USER_INPUT > + *** TEST BUILD: RTEMS_NETWORKING RTEMS_POSIX_API > + *** TEST TOOLS: 7.3.0 20180125 (RTEMS 5, RSB > + a3a6c34c150a357e57769a26a460c475e188438f, Newlib 3.0.0) > + Press any key to start capture engine (20s remaining) > + Press any key to start capture engine (19s remaining) > + Press any key to start capture engine (18s remaining) > + > + Monitor ready, press enter to login. > + > + 1-rtems $ > + > +Capture Engine comes with a set of commands to perform various actions. > + > +Capture Engine Commands > +----------------------- > + > +1) ``copen <buffer-size>``: Used to initialize the Capture Engine with the > + trace buffer size in bytes. By default the Capture Engine is not > initialized > + and not running. > + > +2) ``cwceil <priority-value>``: Capture Engine filter used to put an upper > + limit on the event priority to be captured. > + > + > +3) ``cwfloor <priority-value>``: Capture Engine filter used to put a lower > + limit on the event priority to be captured. > + > + > +4) ``cwglob <on/off>``: Enable or disable the global watch. > + > + > +5) ``cenable``: Enables the Capture Engine. Capture Engine is by default > + disabled after being opened. > + > + > +6) ``cdisable``: Disables the Capture Engine. > + > + > +7) ``ctlist``: Lists the watch and trigger configurations. > + > + > +8) ``ctrace``: Dumps the recorded traces. By default this command displays 24 > + trace records. Repeated use of this command will display all the recorded > + traces. > + > +9) ``cwadd <task-name>``: Add watch on a particular task. > + > + > +10) ``cwtctl <task-name> <on/off>``: Enable or disable watch on a particular > + task. > + > + > +11) ``ctset``: Used to set a trigger. The general form of the command is: > + > +``ctset [-?] type [to name/id] [from] [from name/id]`` > + > +'type' in the above command refers to the type of trigger needed. The types > of > +triggers that currently exist > +are: > + > +- switch : a context switch from one task to another task > +- create : the executing task creates a task > +- start : the executing task starts a task > +- restart : the executing task restarts a task > +- delete : the executing task deletes a task > +- begin : a task is beginning > +- exitted : a task is exitting > + > +Example > +------- > + > +The following is a sample run of the capture testsuite. The test1 command on > +the Capture Engine Command Line Interface (CLI) makes the 'RMON' task invoke > +a call to the 'capture_test_1()' command. This function (in the > +'test1.c' source code) creates and starts three tasks : 'CT1a', 'CT1b' and > +'CT1c'. These tasks are passed the object id of a semaphore as a task > argument. > +This run through traces the context switches between these tasks. > +``cwceil`` and ``cwfloor`` are set to a narrow range of task priorities to > +avoid creating noise from a large number of context switches between tasks we > +are not interested in. > + > +.. code:: shell > + > + *** BEGIN OF TEST CAPTURE ENGINE *** > + *** TEST VERSION: 5.0.0.de9b7d712bf5da6593386fd4fbca0d5f8b8431d8 > + *** TEST STATE: USER_INPUT > + *** TEST BUILD: RTEMS_NETWORKING RTEMS_POSIX_API > + *** TEST TOOLS: 7.3.0 20180125 (RTEMS 5, RSB > + a3a6c34c150a357e57769a26a460c475e188438f, Newlib 3.0.0) > + Press any key to start capture engine (20s remaining) > + Press any key to start capture engine (19s remaining) > + Press any key to start capture engine (18s remaining) > + Press any key to start capture engine (17s remaining) > + > + Monitor ready, press enter to login. > + > + 1-rtems $ copen 50000 > + capture engine opened. > + 1-rtems $ cwceil 100 > + watch ceiling is 100. > + 1-rtems $ cwfloor 102 > + watch floor is 102. > + 1-rtems $ cwglob on > + global watch enabled. > + 1-rtems $ ctset RMON > + trigger set. > + 1-rtems $ cenable > + capture engine enabled. > + 1-rtems $ test1 > + 1-rtems $ cdisable > + capture engine disabled. > + 1-rtems $ ctrace > + 0 0:18:17.462314124 0a010003 CT1a 102 102 102 4096 TASK_RECORD > + 0 0:18:17.462398963 0 0a010003 CT1a 102 102 CREATED > + 0 0:18:17.462647987 249024 0a010003 CT1a 102 102 STARTED > + 0 0:18:17.462904334 256347 0a010003 CT1a 102 102 SWITCHED_IN > + 0 0:18:17.463069129 164795 0a010003 CT1a 102 102 BEGIN > + 0 0:18:17.463335853 266724 0a010003 CT1a 102 102 > SWITCHED_OUT > + 0 0:18:18.461348547 0a010004 CT1b 101 101 101 4096 TASK_RECORD > + 0 0:18:18.461433997 998098144 0a010004 CT1b 101 101 CREATED > + 0 0:18:18.461683631 249634 0a010004 CT1b 101 101 STARTED > + 0 0:18:18.461934485 250854 0a010004 CT1b 101 101 SWITCHED_IN > + 0 0:18:18.462099891 165406 0a010004 CT1b 101 101 BEGIN > + 0 0:18:19.460935339 998835448 0a010004 CT1b 101 101 > SWITCHED_OUT > + 0 0:18:19.461431555 0a010005 CT1c 100 100 100 4096 TASK_RECORD > + 0 0:18:19.461516394 581055 0a010005 CT1c 100 100 CREATED > + 0 0:18:19.461765418 249024 0a010005 CT1c 100 100 STARTED > + 0 0:18:19.462019324 253906 0a010005 CT1c 100 100 SWITCHED_IN > + 0 0:18:19.462184119 164795 0a010005 CT1c 100 100 BEGIN > + 0 0:18:19.462475257 291138 0a010005 CT1c 100 100 > SWITCHED_OUT > + 0 0:18:19.462551551 76294 0a010004 CT1b 101 101 SWITCHED_IN > + 0 0:18:19.960935645 498384094 0a010004 CT1b 101 101 > SWITCHED_OUT > + 0 0:18:19.961012549 76904 0a010003 CT1a 102 100 SWITCHED_IN > + 0 0:18:19.961341528 328979 0a010003 CT1a 102 102 > SWITCHED_OUT > + 1-rtems $ ctrace > + 0 0:18:19.961418433 0 0a010005 CT1c 100 100 SWITCHED_IN > + 0 0:18:19.961672339 253906 0a010005 CT1c 100 100 > SWITCHED_OUT > + 0 0:18:19.961749854 77515 0a010004 CT1b 101 101 SWITCHED_IN > + 0 0:18:20.460967077 499217223 0a010004 CT1b 101 101 > SWITCHED_OUT > + 0 0:18:20.461219763 252686 0a010005 CT1c 100 100 SWITCHED_IN > + 0 0:18:20.461424231 204468 0a010005 CT1c 100 100 TERMINATED > + 0 0:18:20.461747107 322876 0a010005 CT1c 100 100 > SWITCHED_OUT > + 0 0:18:20.461824011 76904 0a010004 CT1b 101 101 SWITCHED_IN > + 0 0:18:20.462015052 191041 0a010004 CT1b 101 101 TERMINATED > + 0 0:18:20.462336707 321655 0a010004 CT1b 101 101 > SWITCHED_OUT > + 0 0:18:20.462414222 77515 0a010003 CT1a 102 102 SWITCHED_IN > + 0 0:18:20.462608924 194702 0a010003 CT1a 102 102 TERMINATED > + 0 0:18:20.462933021 324097 0a010003 CT1a 102 102 > SWITCHED_OUT > + 1-rtems $ ctrace > + 1-rtems $ > + > + > diff --git a/user/tracing/examples.rst b/user/tracing/examples.rst > new file mode 100644 > index 0000000..f51613e > --- /dev/null > +++ b/user/tracing/examples.rst > @@ -0,0 +1,12 @@ > +.. comment SPDX-License-Identifier: CC-BY-SA-4.0 > + > +.. comment: Copyright (c) 2016 Chris Johns <chr...@rtems.org> > +.. comment: All rights reserved. > + > +.. _examples: > + > +Tracing Examples > +**************** > + > +[TBD] > + > diff --git a/user/tracing/index.rst b/user/tracing/index.rst > new file mode 100644 > index 0000000..a879207 > --- /dev/null > +++ b/user/tracing/index.rst > @@ -0,0 +1,33 @@ > +.. comment SPDX-License-Identifier: CC-BY-SA-4.0 > + > +.. comment: Copyright (c) 2016 Chris Johns <chr...@rtems.org> > +.. comment: All rights reserved. > + > +.. _tracing-framework: > + > +RTEMS Tracing Framework > +*********************** > +.. index:: Tracing Framework > + > +RTEMS Tracing Framework is an on-target software based system which helps > track > +the ongoings inside applications, 3rd party packages, and the kernel in real > +time. > + > +Software based tracing is a complex process which requires components on both > +the > +target and the host to work together. However its portability across all > +architectures > +and board support packages makes it a useful asset. A key requirement in > RTEMS > +trace process > +is to take existing code in compiled format (ELF) and instrument it in order > to > +log various events > +and records in real time. However instrumenting of the code for tracing > should > +happen without rebuilding > +the code from the source and without annotating the source with trace code. > + > +.. toctree:: > + > + introduction > + usecases > + examples > + > diff --git a/user/tracing/introduction.rst b/user/tracing/introduction.rst > new file mode 100644 > index 0000000..b4925b2 > --- /dev/null > +++ b/user/tracing/introduction.rst > @@ -0,0 +1,184 @@ > +.. comment SPDX-License-Identifier: CC-BY-SA-4.0 > + > +.. comment: Copyright (c) 2016 Chris Johns <chr...@rtems.org> > +.. comment: All rights reserved. > + > +.. _introduction: > + > +Introduction to Tracing > +*********************** > + > +Tracing is an important function which has several applications including > +identification of complex threading, detection of deadlocks, tracing > +functions along with their argument values, and return values through > +progression of several function calls and audit the performance of an > +application according to required specifications. > + > +RTEMS tracing framework is under development and welcomes contribution by > users. > + > +RTEMS has the following trace components: > + > +- RTEMS :ref:`tracelinker` > +- RTEMS :ref:`capturengine` > +- Common Trace Format Integration > + > + > +RTEMS trace framework can currently function using the following methods. > Both > +of the methods make use > +of the :ref:`tracelinker` : > + > +.. _tracebuffering: > + > +RTEMS Trace Using Trace Buffering > +================================= > + > +This scheme of tracing goes through the flow of events described in a > +subsequent flowchart: > + > +Step 1: The user creates an application and user configuration file. The > +configuration file specifies the use of the trace buffer generator and other > +standard initializations. The user then configures her BSP and invokes the > +trace linker using a command to link the application executable. The trace > +linker uses the application files in compiled format (ELF) and the libraries > +used to build the application for performing this link. > + > +Step 2: The RTEMS Trace Linker reads the user’s configuration file and that > +results in it reading the standard Trace Buffering Configuration files > +installed with the RTEMS Trace Linker. The trace linker uses the target > +compiler and linker to create the trace enabled application executable. It > +wraps the functions defined in the user’s configuration with code that > captures > +trace records into the statically allocated buffer. The trace wrapper code is > +compiled with the target compiler and the resulting ELF object file is added > +to the standard link command line used to link the application and the > +application is re-linked using the wrapping option of the GNU linker. > + > +Step 3: The trace linker creates an executable which is capable of running on > +the target hardware or simulator. > + > +Step 4: RTEMS shell provides the “rtrace” command to display and save trace > +buffers. > + > +.. comment: taken from https://devel.rtems.org/wiki/Developer/Tracing > +.. figure:: ../../images/user/rtems-trace-buffering.png > + :align: center > + :width: 75% > + > + > +.. _printk: > + > +RTEMS Trace Using Printk > +======================== > + > +This scheme of tracing goes through the flow of events described in a > +subsequent flowchart: > + > +Step 1: The user creates an RTEMS application in the normal manner as well as > +a Trace Linker configuration file. The configuration file specifies using the > +Printk trace mode and the functions to trace. The user invokes the Trace > Linker > +with the configuration and the normal link command line used to the link the > +application executable. The application ELF object files and libraries, > +including the RTEMS libraries are standard and do not need to be built > specially. > + > +Step 2: The RTEMS Trace Linker reads the user's configuration file and that > +results in it reading the standard Printk Trace Configuration files installed > +with the RTEMS Trace Linker. The trace linker uses the target compiler > +and linker to create the trace enabled application executable. It wraps the > +functions defined in the user's configuration with code that prints the entry > +with arguments and exit and return value if any. The trace wrapper code is > +compiled with the target compiler and the resulting ELF object file is added > +to the standard link command line used to link the application and the > +application is relinked using the wrapping option of the GNU linker. > + > +Step 3: The trace linker creates and RTEMS ELF executable that can be run on > +the target hardware or simulator. > + > +Step 4: The application is run in the hardware directly or using a debugger. > +The printk() output appears on the target console and the user can save that > +to a file. > + > +.. comment: taken from https://devel.rtems.org/wiki/Developer/Tracing > +.. figure:: ../../images/user/rtems-trace-printk.png > + :align: center > + :width: 75% > + > +The :ref:`examples` section describes generation of traces using both of the > +aforementioned techniques using the `fileio` testsuite available with RTEMS > +installation. > + > +RTEMS Trace Using CTF > +===================== > + > +`Common Trace Format <http://diamon.org/ctf/>`_ (CTF) is a binary trace > format > +which is fast to write and has great flexibility. It allows traces to be > +developed by bare-metal applications or by any other C/C++ system. RTEMS > +tracing framework can benefit from these features of CTF. > + > +A typical CTF *trace* consists of multiple *streams* of binary *events*. The > +*metadata* stream is a mandatory stream which describes the layout of all the > +other streams in a trace. This metadata stream is written using *Trace Stream > +Description Language* (TSDL). > + > +.. comment: image taken from > view-source:http://diamon.org/ctf/img/ctf-trace.png > +.. comment: Not generating a copyright in the high chance we decide to not > keep > +.. comment: a descriptive section on CTF > + > +.. figure:: ../../images/user/ctf-trace.png > + :align: center > + :width: 75% > + > +A binary *stream* is further a concatenation of several packets each > containing > +the following: > + > +- A packet header > +- An optional packet context > +- A set of concatenated events each containing: > + - An event header > + - A stream-specific context > + - An event-specific context > + - A payload > + > +.. comment: taken from http://diamon.org/ctf/img/ctf-stream-packet.png > +.. comment: Not generating a copyright in the high chance we decide to not > keep > +.. comment: a descriptive section on CTF > + > +.. figure:: ../../images/user/ctf-stream-packet.png > + :align: center > + :width: 75% > + > +All the headers, contexts and payloads are written in TSDL using CTF data > +types. CTF supports a rich set of configurable datatypes which makes it > +possible to describe a larger variety of binary structure. Moreover types > +in CTF are organized as type classes where type specifications can be > inherited > +to allow deriving types. These factors make CTF flexible. CTF enables fast > +writing of binary data as it usually involves appending memory contents, > +as it is to a binary CTF stream. CTF streams are capable of being sent or > +received over the network without any data being written to disk and hence > +can be useful in transporting traces from the target to the host machine for > +analysis. > + > +Due to these advantages tracing using CTF will prove to be beneficial for the > +users. This method of tracing is currently under development. Currently the > +RTEMS tracing framework is able to output trace data in the form of trace > buffers, > +console output and csv files. A conversion tool which transforms these trace > +output formats to CTF will be viable approach to generating CTF traces. In > this > +regard we utilize babeltrace, which is described in the following section. > + > +Babeltrace > +---------- > + > +Babeltrace is an open source trace format converter which can be used to > +convert RTEMS traces into CTF. It is also a reference parser implementation > +of CTF. Babeltrace currently supports the following output formats for > traces: > + > +- Text > +- CTF > +- CTF-metadata > +- Dummy > +- lttng-live > + > +Babeltrace comes in the form of a library, python bindings (python3) and > +command line tool called ``babeltrace``. To install babeltrace on your host > +you can install a distribution package or build from source using tarballs or > +git repositories of babeltrace. Refer to http://diamon.org/babeltrace/ for > +further details. > + > diff --git a/user/tracing/tracelinker.rst b/user/tracing/tracelinker.rst > new file mode 100644 > index 0000000..4bef4e5 > --- /dev/null > +++ b/user/tracing/tracelinker.rst > @@ -0,0 +1,294 @@ > +.. comment SPDX-License-Identifier: CC-BY-SA-4.0 > + > +.. comment: Copyright (c) 2016 Chris Johns <chr...@rtems.org> > +.. comment: All rights reserved. > + > +.. _tracelinker: > + > +Trace Linker > +************ > + > +RTEMS trace linker is a post link tool central to the RTEMS trace framework. > It > +is installed as a part of the RTEMS Tool Project.The RTEMS Trace Linker is a > +post link tool that performs a re-link of your application to produce a trace > +executable. A trace executable has been instrumented by the RTEMS Trace > Linker > +with additional code that implements software tracing. A key requirement of > the > +trace process in RTEMS is to take existing code in a compiled format (ELF) > and > +instrument it without rebuilding that code from source and without annotating > +that source with trace code. > + > + > +Command Line > +============ > + > +A typical command to invoke the trace linker consists of two parts separated > by > +``--``. The first part controls the trace linker and provides the various > +options it needs and the second part is a standard linker command line you > would > +use to link an RTEMS application. The current command line for trace linker > +consists of: > + > +.. code-block:: shell > + > + $ rtems-tld -h > + rtems-trace-ld [options] objects > + Options and arguments: > + -h : help (also --help) > + -V : print linker version number and exit (also --version) > + -v : verbose (trace import parts), can supply multiple times > + to increase verbosity (also --verbose) > + -w : generate warnings (also --warn) > + -k : keep temporary files (also --keep) > + -c compiler : target compiler is not standard (also --compiler) > + -l linker : target linker is not standard (also --linker) > + -E prefix : the RTEMS tool prefix (also --exec-prefix) > + -f cflags : C compiler flags (also --cflags) > + -r path : RTEMS path (also --rtems) > + -B bsp : RTEMS arch/bsp (also --rtems-bsp) > + -W wrapper : wrapper file name without ext (also --wrapper) > + -C ini : user configuration INI file (also --config) > + -P path : user configuration INI file search path (also --path) > + > +The trace linker generates code that needs to be compiled and linked to the > +application executable so it needs to know the target compiler and `CFLAGS`. > +There are a couple of ways to do this. The simplest is to provide the path to > +RTEMS using the `-r` option and the architecture and BSP name in the standard > +RTEMS format of arch/bsp. The trace linker will extract the compiler and > flags > +used to build RTEMS and will use them. If you require specific options you > can > +use the `-f`, `-c`, `-l` and `-E` options to provide them. If the functions > +you are tracing use types from your code then add the include path to the > +`CFLAGS`. > + > +The trace linker requires you to provide a user configuration file using the > +`-C` or ``--config`` option. This is an INI format file detailed in the > +Configuration section. You can also provide an INI file search path using the > +`-P` option. > + > +If you are working with new configuration files and you want to view the > files > +the trace linker generates add the `-k` option to keep the temporary files, > and > +`-W` to specify an explicit wrapper C file name. If you set the > ``dump-on-error`` > +option in the configuration options section you will get a dump of the > +configuration on an error. > + > + > +Configuration (INI) files > +========================= > + > +The Trace Linker is controlled using configuration files. Configuration files > +are categorized into 3 types: > + > +- User Configuration: These are specific to the user application to be > traced. > + This file initializes the values of the trace generator, triggers, enables > and > + traces. > + > +- Tracer Configuration: These are like a library of common or base trace > + functions that can be referenced by an application. These files tend to > hold > + the details needed to wrap a specific set of functions. Examples provided > with > + the RTEMS Linker are the RTEMS API and Libc. > + > +- Generator Configuration: This is used to encapsulate a specific method of > + tracing. Rtems currently provides generators for trace buffering, printk > and > + printf. > + > +The configuration files are in the *INI file format* which is composed of > +`sections`. Each section has a section name and set of *keys* which consist > +of *names* and *values*. A typical key is of the form ``name=value``. Keys > +can be used to include other INI files using the include key name. This is > +shown in the following example where the values indicate rtems and rtld-base > +configuration files: > + > +.. code-block::shell > + include = rtems.ini, rtld-base.ini > + > +The trace linker also uses values in keys to specify other sections. In this > +example the functions name > +lists test-trace-funcs and that section contains a headers key that > references > +a further section test-headers: > + > +.. code-block::shell > + functions = test-trace-funcs, rtems-api > + > + [test-trace-funcs] > + ; Parsed via the 'function-set', not parse as a 'trace'. > + headers = test-headers > + > + [test-headers] > + header = '#include "test-trace-1.h"' > + > +The format of a configuration file is explained next. Snippets of the > +fileio-trace.ini file have been used for explicit understanding. This file > can > +be downloaded from `here > +<https://devel.rtems.org/attachment/wiki/Developer/Tracing/Trace_Buffering/filei > +o-trace.ini>`_. > + > +Tracer Section > +-------------- > + > +The topmost level section is the ``tracer`` section. It can contains the > +following keys: > + > +- name: The name of trace being linked. > + > +- options: A list of option sections. > + > +- defines: A list of sections containing defines or define record. > + > +- define: A list of define string that are single or double quoted. > + > +- enables: The list of sections containing enabled functions to trace. > + > +- triggers: The list of sections containing enabled functions to trigger > trace > + on. > + > +- traces: The list of sections containing function lists to trace. > + > +- functions: The list of sections containing function details. > + > +- include: The list of files to include > + > + > +.. code-block:: shell > + [tracer] > + name = File IO tracer > + ; > + ; The configuration > + ; > + options = fileio-options > + traces = fileio > + defines = fileio > + enables = fileio > + triggers = fileio > + functions = fileio-funcs, rtems-api, rtems-posix, libc-heap > + include = rtems.ini, rtld-base.ini, rtld-trace-buffer.ini, libc-heap.ini > + > + > +Options section > +--------------- > + > +The options section in the fileio-trace.ini is called the `fileio-options`. A > +general options section can contain following sets of keys: > + > +- dump-on-error: Dump the parsed configuration data on error. The value can > be > + true or false. > + > +- verbose: Set the verbose level. The value can be true or a number value. > + > +- prefix: The prefix for the tools and an install RTEMS if rtems-path is not > + set. > + > +- cc: The compiler used to compile the generated wrapper code. Overrides the > + BSP configuration value if a BSP > + is specified. > + > +- ld: The linker used to link the application. The default is the cc value as > + read from the BSP configuration > + if specificed. If your application contains C++ code use this setting to > the > + change the linker to g++. > + > +- cflags: Set the CFLAGS used to compiler the wrapper. These flags are > + pre-pended to the BSP read flags if a BSP > + is specified. This option is used to provide extra include paths to header > + files in your application that contain > + types any functions being traced reference. > + > +- rtems-path: The path to an install RTEMS if not installed under the prefix. > + > +- rtems-bsp: The BSP we are building the trace executable for. The is an arch > + and bsp pair. For example sparc/erc32. > + > +.. code-block:: shell > + > + [fileio-options] > + dump-on-error = true > + ; > + ; Tools > + ; > + prefix = /development/rtems/5 > + rtems-path = /development/rtems/kernel/5 > + rtems-bsp = sparc/erc32 > + ; > + ; Generator options. > + ; > + gen-enables = enable > + gen-triggers = enable > + > + > +Trace Section > +-------------- > + > +A trace section defines how trace wrapper functions are built. To build a > trace > +function that wraps an existing function in an ELF object file or library > archive > +we need to have the function's signature. A signature is the function's > declaration > +with any types used. The the signature has specific types we need access to > those > +types which means the wrapper code needs to include header files that define > those > +types. There may also be specific defines needed to access those types. > + > +- generator: The generator defines the type of tracing being used. > + > +- headers: List of sections that contain header files keys. > + > +- header: A header key. Typically the include code. > + > +- defines: List of sections that contain defines. > + > +- define: A define key. Typically the define code. > + > +- signatures: List of function signature sections. > + > +- trace: Functions that are instrumented with trace code. > + > + > +[TBD] > + > + > +Function Wrapping > +================= > + > +The trace linker's major role is to wrap functions in the existing executable > +with trace code. The directions on how to wrap application functions is > +provided by the generator configuration. The wrapping function uses a > +GNU linker option called --wrap=symbol. The GNU Ld manual states: > + > +"Use a wrapper function for symbol. Any undefined reference to symbol will be > +resolved to __wrap_symbol. Any undefined reference to __real_symbol will be > +resolved to symbol." > + > +The trace linker generates C code with a wrapper for each function to be > +instrumented. The trace code generated is driven by the configuration INI > +files. > + > + > +Function Signatures > +=================== > + > +A function signature is the function's declaration. It is the name of the > +function, the return value and the arguments. Tracing using function > +wrappers requires that we have accurate function signatures and ideally > +we would like to determine the function signature from the data held in > +ELF files. ELF files can contain DWARF data, the ELF debugging data format. > +In time the trace project would like to support libdwarf so the DWARF data > +can be accessed and use to determine a function's signature. This work is > +planned but not scheduled to be done and so in the meantime we explicitly > +define the function signatures in the configuration files. > + > + > +Development > +=========== > + > +The Trace Linker is part of the RTEMS tools git repository available at : > +https://git.rtems.org/rtems-tools > +The RTEMS tools project utilizes the waf build system. Use the following > +commands in the topmost build directory to build the tools project: > + > +First we configure using: > + > +.. code-block:: shell > + > + $./waf configure --prefix=$HOME/development/rtems/5 > + > +Then we build and install using: > + > +.. code-block:: shell > + > + $./waf build install > + > + > diff --git a/user/tracing/usecases.rst b/user/tracing/usecases.rst > new file mode 100644 > index 0000000..20ce43d > --- /dev/null > +++ b/user/tracing/usecases.rst > @@ -0,0 +1,129 @@ > +.. comment SPDX-License-Identifier: CC-BY-SA-4.0 > + > +.. comment: Copyright (c) 2016 Chris Johns <chr...@rtems.org> > +.. comment: All rights reserved. > + > +.. _usecases: > + > +Tracing Use Cases > +***************** > + > +Following are the use cases of the tracing framework that are currently under > +development: > + > +Function Tracing > +================ > + > +Tracing the entry and exit of a function as well as the values of the > arguments > +and > +return values can prove to be an important application for the tracing > +framework. > + > +Objective > +--------- > + > +This use case can prove to be helpful in debugging of applications for the > +users. It can also > +be used to understand the working of existing application code bases. > Capturing > +of argument and > +return values maybe useful in tracking unexpected output results from the > +applications. > + > +Requirements > +------------ > + > +The current tracing framework provides this functionality with > +:ref:`tracebuffering`. The output is > +provided in the form of printing on console or saving the buffer in the form > of > +a bin file. In order to > +develop this use case using CTF we need to be able to convert this RTEMS > trace > +output into CTF. This could > +be done using babeltrace. The converted CTF traces would then be sent over to > +the host using a transport > +mechanism. > + > +Example > +------- > + > +As a start to the development of function tracing using CTF we can work on > the > +fileio > +sample testsuite and trace all the calls to malloc, calloc, free and realloc > +functions. > +Along with the calls made to these functions the trace must also capture the > +values of > +their arguments at entry and the return values at function exit. As an > example > +of an application > +having the following progression of function calls: > + > +.. code-block:: c > + > + #include <stdlib.h> > + int main(int argc, char** argv) > + { > + int* a = malloc(sizeof(int)); > + free(a); > + a = calloc(1, sizeof(int)); > + return 0; > + } > + > + > +The trace of such an application must be output of the following kind: > + > +.. code-block:: shell > + > + Timestamp1 entry of malloc > argument value > + Timestamp2 exit of malloc < return value > + Timestamp3 entry of free > argument value > + Timestamp4 exit of free < return value (null) > + Timestamp5 entry of calloc > argument1 value, argument2 value > + Timestamp6 exit of calloc < return value1 > + > +There could be additional columns of details including current priority, task > +state etc. > + > + > +Tracing Thread Operations > +========================= > + > +Tracing thread creation, switching and termination operation in a thread's > +lifetime within an application. > + > +Objective > +--------- > + > +Real time applications inherently utilize parallel programming which entails > +several > +tasks executing simultaneously and competing for common resources. On single > +processor systems > +the CPU performs context switching between each of these tasks rapidly. By > +tracing the creation and > +termination of tasks as well as the context switches between them one can > +possibly identify probable race > +conditions or complex threading operations. > + > +Requirements > +------------ > + > +[TBD] > + > +Example > +------- > + > +A sample trace tracking two tasks Ta and Tb could have an output of the > +following kind: > + > +.. code-block:: shell > + > + Timestamp1 taskid Ta CREATED > + Timestamp1 taskid Ta SWITCHED-IN > + Timestamp1 taskid Ta BEGIN > + Timestamp1 taskid Tb CREATED > + Timestamp1 taskid Ta SWITCHED-OUT > + Timestamp1 taskid Tb SWITCHED-IN > + Timestamp1 taskid Tb BEGIN > + Timestamp1 taskid Tb SWITCHED-OUT > + Timestamp1 taskid Tb TERMINATED > + Timestamp1 taskid Ta SWITCHED-IN > + Timestamp1 taskid Ta SWITCHED-OUT > + Timestamp1 taskid Ta TERMINATED > + > -- > 2.7.4 > > _______________________________________________ > devel mailing list > devel@rtems.org > http://lists.rtems.org/mailman/listinfo/devel _______________________________________________ devel mailing list devel@rtems.org http://lists.rtems.org/mailman/listinfo/devel
