fix(system_monitor): multithreading support for boost::process

[v-nakayama7440-esol]

Signed-off-by: v-nakayama7440-esol v-nakayama7440@esol.co.jp

Description

boost::process::pipe internally creates file descriptor. However, this file descriptor does not support multithreading because O_CLOEXEC is not set. Because of this, when each thread of SystemMontor uses boost::process to create a child process, the file descriptors of boost::process::pipe conflict between child processes. As a result, the child process waits for the file descriptor to be released.

In this PR, the SystemMonitor application creates file descriptor with O_CLOEXEC set and passes it to boost::process::pipe to eliminate the wait for child process to release file descriptor.

Related links

• The issue Diagnostic topic of process_monitor sometimes may not be sent periodically #939 was still observed after the fix fix(system_monitor): move top command execution to a timer #948.
• This is related to the boost::process issue and to apply the workaround described in POSIX multi-thread parallel childs invoked with piped std_in often do not receive STDIN close boostorg/process#169 (comment).

Tests performed

Process Monitor's /diagnostics topic message timestamp interval is essentially about 1 second (diagnostic_updater event execution cycle is 1hz). However, before the fix, the interval would occasionally be about 2 seconds.

Graph before fix (vertical axis unit is msec, horizontal axis unit is message order):

After the fix, Process Monitor confirmed that the timestamp interval for messages on the /diagnostics topic was not always reaching 2 seconds. Monitors other than Process Monitor were also checked in the same way.

Graph after fix (vertical axis unit is msec, horizontal axis unit is message order):

Additional tests performed

In order to check if no side effects come by this fix, verified the all of /diagnostics topics are sent periodically and notified as OK during normal operation.

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[ito-san]

@v-nakayama7440-esol Could you please provide some measurements such as visualized interval of before and after the fix in Tests performed above?

[v-nakayama7440-esol]

@ito-san
The graphs of Process Monitor before fix and Process Monitor and CPU Monitor after fix are attached to "Tests performed".

[codecov]

Codecov Report

Merging #1714 (9420251) into main (ae56406) will decrease coverage by 0.05%.
The diff coverage is 0.00%.

@@            Coverage Diff             @@
##             main    #1714      +/-   ##
==========================================
- Coverage   10.67%   10.61%   -0.06%     
==========================================
  Files        1109     1109              
  Lines       78619    79029     +410     
  Branches    18587    18587              
==========================================
  Hits         8392     8392              
- Misses      61312    61722     +410     
  Partials     8915     8915              

Flag	Coverage Δ		*Carryforward flag
differential	0.00% <0.00%> (?)
total	10.65% <0.00%> (ø)		Carriedforward from ae56406

*This pull request uses carry forward flags. Click here to find out more.

Impacted Files	Coverage Δ
...ystem_monitor/src/cpu_monitor/cpu_monitor_base.cpp	0.00% <0.00%> (ø)
...tem/system_monitor/src/hdd_monitor/hdd_monitor.cpp	0.00% <0.00%> (ø)
...tem/system_monitor/src/mem_monitor/mem_monitor.cpp	0.00% <0.00%> (ø)
...tem/system_monitor/src/ntp_monitor/ntp_monitor.cpp	0.00% <0.00%> (ø)
...em_monitor/src/process_monitor/process_monitor.cpp	0.00% <0.00%> (ø)

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[ito-san]

Verified the issue was gone after 1 hour test in cargo project.

[ito-san]

Verified in bus project with humble.

[ito-san]

LGTM