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I'm using a Pi to command an home-made robot. For that I run several python scripts (and one programme in C++), they consume many CPU. I want to let the robot working for several days in a row. But after few hours it seems the Pi closes all the terminal.

At first I thought the Pi rebooted during the night. But once it did it during the day, and I could check that my SSH connection was not closed.

Is there a kind of protection in the Pi that closes all the process if I requiring to much CPU? And is there a way to check what happened, like a log file? I already check last -x for any savage reboot.

If you need any further information, please let me know. I don't know what could be useful. Thanks in advance.

NB: the C++ program takes itself 100% of one CPU.

UPDATE with info from comment:
I'm using RPi 4 with 8 GB of RAM. I'm using an homemade power delivery that supplies 5 V - 3 A. I never got problems with it, the Pi doesn't shutdown and never display the lightning. Moreover in last -x I couldn't find any power shutdown.

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  • What Raspberry Pi version do you use? What power supply do you use?
    – Ingo
    Commented Jan 29, 2021 at 17:37

2 Answers 2

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Is there a kind of protection in the Pi that closes all the process if I requiring to much CPU?

For CPU, no. However, there is a mechanism which kills processes if the system runs out of memory. You can see those with:

grep -i 'killed process' /var/log/messages

If you find a process which is getting killed, check it for memory leaks.

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  • The command returned nothing, so I guess no killed happened. But I'll try it again just after the problem happens.
    – Dark Patate
    Commented Feb 1, 2021 at 5:52
  • Does this process kills everything in case of memory leakage? I mean I have one Python script and one C++ program that are running together. If one is fulling the memory, does the Pi stop everything, or just the incriminated program?
    – Dark Patate
    Commented Feb 1, 2021 at 6:03
  • @DarkPatate Out-Of-Memory handler certainly doesn't kill 'everything'. It normally kills one process at a time. However, your scripts may interact with each other in a way that makes them fail together. E.g. if you run find / | grep and you kill find, grep will also be killed when it tries to get new data from find.
    – Dmitry Grigoryev
    Commented Feb 1, 2021 at 8:08
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You can take a look at the logfiles in /var/log and look at the output of the dmesg command to see if there is any hints. The Pi (or any other computer running Linux) should not terminate a process if it is using too much cpu, just get slower. But running out of memory could cause that. Another option is, that there is a bug in the programs that terminates them.

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  • I should check, the script, indeed, a bug could be a problem. Maybe I should add a system("PAUSE") at the end of the script, to see if it is the problem. I hope it's not RAM leakage, it'd would be more problematic to correct ^^
    – Dark Patate
    Commented Feb 1, 2021 at 5:55

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