High CPU Usage: Process with Changing PID

Cleon · 23 March 2024 13:41

Hello Manjaro community,

I’ve encountered an issue on my Manjaro Linux system where a process with a constantly changing PID is causing high CPU usage at constant intervals. After some investigation, I’ve observed that the process runs the command:

/usr/bin/ps ax -weo pid,rssipmem,vsize,uname:50,pcpu,start_time,state,groupinice,cputime,session,cmd --no-headings

This process consumes 100% CPU at times and then disappears, only to respawn with a different PID later withing seconds. This behavior has been quite disruptive to my system’s performance.

Note: The process does not show up on “top” or “htop” it only shows up while looking through “Stacer”

I’ve tried running a backtrace using gdb, but since the PID keeps changing, it’s challenging to pinpoint the root cause of the issue.

Here’s what I’ve tried so far:

Using pgrep to dynamically identify the PID of the process.
Running gdb with the identified PID to gather a backtrace.

However, I haven’t been successful in identifying the cause of this mysterious process.

I would greatly appreciate any insights or suggestions from the community on how to further diagnose and resolve this issue or how I can reduce my CPU usage overall. Additionally, if anyone has encountered a similar problem or has any tips on debugging high CPU usage caused by processes with changing PIDs, please share your experiences.

Thank you in advance for your help!

System Information:

Operating System: Manjaro Linux x86_64
Kernel: 6.6.19-1-MANJARO
Desktop Environment: Xfce 4.18
CPU: Intel i3-2120 (4) @ 3.300GHz
GPU: NVIDIA GeForce 8400 GS Rev. 2

Aragorn · 23 March 2024 13:54

Welcome to the forum!

Cleon:

After some investigation, I’ve observed that the process runs the command:
/usr/bin/ps ax -weo pid,rssipmem,vsize,uname:50,pcpu,start_time,state,groupinice,cputime,session,cmd --no-headings

It’s probably a system monitor widget of some sorts that you have. The command ps lists running processes. See its man page…

man ps

Nothing nefarious going on there so far. Now, if you were experiencing performance issues, then that would be whole other matter.

MrLavender · 23 March 2024 14:34

It is Stacer that is running that command…

github.com

oguzhaninan/Stacer/blob/a44d0565a05c996b1058f950f1d308e1964c8320/stacer-core/Info/process_info.cpp#L14


      
          
          void ProcessInfo::updateProcesses()
          {
              processList.clear();
          
              try {
          
                  QStringList columns = { "pid", "rss", "pmem", "vsize", "uname:50", "pcpu", "start_time",
                                          "state", "group", "nice", "cputime", "session", "cmd"};
          
                  QStringList lines = CommandUtil::exec("ps", {"ax", "-weo", columns.join(","), "--no-headings"})
                          .trimmed()
                          .split(QChar('\n'));
          
                  if (! lines.isEmpty()) {
                      QRegExp sep("\\s+");
                      for (const QString &line : lines) {
                          QStringList procLine = line.trimmed().split(sep);
          
                          if (procLine.count() >= columns.count()) {
                              Process proc;

Cleon · 24 March 2024 04:28

This post didn’t exist. Shh (thank you so much for answering my braindead question )

system · 25 March 2024 16:29

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