openairinterface5g/common/utils/T/DOC/T/basic.md

Basic usage of the T

Compilation

softmodem side

Simply call build_oai the usual way, for example ./build_oai --eNB -w USRP. The T tracer is compiled in by default.

tracer side

Go to the directory common/utils/T/tracer and do make. This will locally compile all tracer executables, and place them in common/utils/T/tracer. If you wish to keep source and build separate, go to your existing build directory (typically cmake_targets/ran_build/build), and do make T_tools (or ninja T_tools). After that, the executables will be in <build-dir>/common/utils/T/tracer.

In case of failure with one of the following errors:

/usr/bin/ld: cannot find -lXft

or

-- Checking for module 'xft'
--   No package 'xft' found
CMake Error at /usr/share/cmake-3.16/Modules/FindPkgConfig.cmake:463 (message):
  A required package was not found

Run:

sudo apt-get install libx11-dev libpng-dev libxft-dev

Run the softmodem

Run the softmodem with the option --T_stdout 2 and it will wait for a tracer to connect to it before processing. (This option is confusing and may change in the future.)

cd cmake_targets/ran_build/build
sudo ./lte-softmodem -O [configuration file] --T_stdout 2

Additional options can be passed to the softmodem.

The option --T_nowait lets the processing start immediately without first waiting for a tracer.

The option --T_port [port] changes the default port used by the softmodem to wait for a tracer. The default port is 2021.

The option --T_dont_fork allows one to use gdb to debug problems with the softmodem. Note that you then may have some "zombie" processes after crashes, in which case you can run sudo killall -9 lte-softmodem to get rid of them.

The option --T_stdout also accepts values 0 (to disable output on the terminal and only use the T tracer) and 1 (to disable the T tracer and only output on the terminal). The default is 1.

Run a tracer

Go into the directory common/utils/T/tracer and run for example the enb tracer:

#in common/utils/T/tracer directory
./enb -d ../T_messages.txt

You can also run it from cmake_targets/ran_build/build/ directory:

# in cmake_targets/ran_build/build directory
./common/utils/T/tracer/enb -d ../../../common/utils/T/T_messages.txt

To trace a remote program, use the -ip option. For example, if you want to trace a program running on 192.168.12.148 do:

# in common/utils/T/tracer directory
./enb -d ../T_messages.txt -ip 192.168.12.148

A graphical user interface will appear with which you can interact to control the monitoring. See there for more documentation about the enb tracer.

It is possible to run several tracers at the same time. See here.