Here descibes ROS2 tracepoint related information, this is public info but not so organized well because this is mostly my own note to keep this in the mind. nobody blames on it. ROS2 tracepoint is actually depends on LTTng so knowing LTTng is to help to understand ROS2 tracepoint.
LTTng are the kernel modules, so that you can see a bunch of ko via lsmod command. Notable features are CTF(Common Trace Format) support, tracepoint, function tracer, monitoring and kprobes. LTTng is context aware so that able to attach context information to event in the trace.
Local mode
LTTng writes the traces to the file system of the machine it traces (target system).
Network streaming mode
LTTng sends the traces over the network to a relay daemon running on a remote system.
Snapshot mode
LTTng does not write the traces by default. Instead, you can request LTTng to take a snapshot, that is, a copy of the tracing session’s current sub-buffers, and to write it to the target’s file system or to send it over the network to a relay daemon running on a remote system.
Live mode
This mode is similar to the network streaming mode, but a live trace viewer can connect to the distant relay daemon to view event records as LTTng generates them.
and there are so far five tracing domains are supported,
$ sudo ufw status verbose
Status: active
Logging: on (low)
Default: deny (incoming), allow (outgoing), disabled (routed)
New profiles: skip
To Action From
-- ------ ----
<ssh port> ALLOW IN Anywhere
<ssh port> (v6) ALLOW IN Anywhere (v6)
$ timedatectl status
Local time: Tue 2020-03-17 17:37:26 JST
Universal time: Tue 2020-03-17 08:37:26 UTC
RTC time: Tue 2020-03-17 08:37:27
Time zone: Japan (JST, +0900)
System clock synchronized: yes
systemd-timesyncd.service active: yes
RTC in local TZ: no
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
@ WARNING: UNPROTECTED PRIVATE KEY FILE! @
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
Permissions 0644 for '/home/yu_uchida/.ssh/id_rsa' are too open.
It is required that your private key files are NOT accessible by others.
This private key will be ignored.
bad permissions: ignore key: /home/yu_uchida/.ssh/id_rsa
Permission denied (publickey).
fatal: Could not read from remote repository.
shell$xclbinutil --input streaming_lap_filter5.xclbin --dump-section BITSTREAM:RAW:streaming_lap_filter5.bit
XRT Build Version: 2.6.0 (2019.2_Ultra96)
Build Date: 2020-03-26 13:46:25
Hash ID: 4a669990dd872f3b683009c0e2200b3bd3d2a9c0
------------------------------------------------------------------------------
Warning: The option '--output' has not been specified. All operations will
be done in memory with the exception of the '--dump-section' command.
------------------------------------------------------------------------------
Reading xclbin file into memory. File: streaming_lap_filter5.xclbin
Section: 'BITSTREAM'(0) was successfully written.
Format: RAW
File : 'streaming_lap_filter5.bit'
Leaving xclbinutil.
ZynqMP-FPGA-XRT をインストールした際に zocl (MPSoC Edge Device 用の Linux カーネルモジュール)もインストールされています。ただしzocl は Linux にインストールしただけでは有効になりません。zocl を有効にするためには Device Tree が必要です。そこで次のような Device Tree を用意しています。
zocl.dts を Device Tree Overlay します。 dtbicfg.rb というDevice Tree Overlay 用の ruby スクリプトを用意していますので、こちらを使います。
shell$./dtbocfg.rb --install zocl --dts zocl.dts
<stdin>:14.16-18.6: Warning (unit_address_vs_reg): /fragment@1/__overlay__/zyxclmm_drm: node has a reg or ranges property, but no unit name
shell$./streaming_lap_filter5.exe streaming_lap_filter5.xclbin
Using FPGA binary file specfied through the command line: streaming_lap_filter5.xclbin
Found Platform
Platform Name: Xilinx
Loading: 'streaming_lap_filter5.xclbin'
total time = 0.001533 sec
Success HW and SW results match
プログラミングのためにLinuxを使う理由は、Linuxにはプログラミング用のソフトウェアが豊富に存在し、便利だから。
さらに、 Linux は GNU General Public Licence (グヌー・ジェネラル・パブリック・ライセンス、GPL) というライセンスの下で提供されているため、基本的に無料で利用できる。
これは膨大な数の PC を用意することになるサーバー運営において、大きくコストを下げることができるというメリットがある。
そのためWebプログラミングの世界では、広くLinuxが利用されている。
