DUG Insight User ManualFrequently Asked QuestionsFrequently Asked Questions PerformanceIn Linux, why does Insight run out of memory for no good reason?

In Linux, why does Insight run out of memory for no good reason?

Insight is a multi-threaded application. Using multiple threads lets a program run more efficiently and also takes advantage of multiple CPUs and CPU cores. When Insight starts, it prepares a pool of "worker threads", ready to perform calculations and collect results.

In the Linux OS, threads and processes are handled very similarly. There is a default setting that limits the total number a user can have at any one time. The default setting is often very low and not appropriate for a single-user workstation.

Check your limits

These commands should all be run from a terminal window.

  • To find the maximum number of threads and processes a single user can have at any one time: ulimit -a
    • Several pieces of information are returned, look for: max user processes
    • For a single-user workstation or virtual machine, this value can be set to a much larger number (e.g. 100000) without causing issues.
  • To find the current number of running threads -- this number will vary depending on the number of programs and activity on the machine:
    1. ps -elfT | wc -l OR
    2. cat/proc/loadavg
      1. Look at the fourth column (it includes a '/' character).
      • This field shows: "currently executing processes" / "total processes"
      • e.g. 0.72 0.58 0.48 2/867 19334 -> 2 executing processes / 867 total
  • To find the the total limit across all users for the machine:
    • sysctl -a | grep kernel.pid_max

Update the limit

These commands require administrator/root permissions. Be careful when making changes to system files or have your IT administrator do it for you.

  • Set the process limit to a new value. The limit will return to the default when the machine is restarted.
    • ulimit -u 10000

Updating the limit permanently depends on the version of Linux you are using.

 

Note: You must completely log out of the account and log back in for these changes to take effect.

 

If you are using PAM, these settings can be configured in:

  • Configuration file: /etc/security/limits.conf
  • These lines set the limit for all users:
*          soft    nproc     16384
*          hard    nproc     16384

If you are using a RedHat variant, you can try:

  • Configuration file: /etc/security/limits.d/90-nproc.conf
  • These lines set the limit for all users:
*          soft    nproc     16384
*          hard    nproc     16384