Tuning System Limits

When dealing with large or complex models, you can easily reach the limits of your system. For example, you cannot open more than a fixed number of files. You can try the command “limit –a” to check them.

File limits: “Could not open ...”

You may see the following error:

msg="Could not open "/var"", file=../model/dce-manager.cc, line=149
terminate called without an active exception

This error masks error “24 Too many open files”. The cause of this is that the simulation process exceeded the limit of open files per process. Check the limit of open files per process with “ulimit -n” To solve it, you can edit file /etc/security/limits.conf and add the following lines at the end:

*         hard    nofile      65536
*         soft    nofile      65536

or

myuser         hard    nofile      65536
myuser         soft    nofile      65536

Processes limit: “Resource temporarily unavailable”

In this case you may see the an error like the following:

assert failed. cond="error == 0", msg="error=Resource temporarily unavailable",
file=../model/pthread-fiber-manager.cc, line=321
terminate called without an active exception

pthread-fibder-manager invokes pthread_create this is what raises the “Resource temporarily unavailable”. This problem might be triggered because the maximum number of user processes is not big enough. Use “ulimit -u” to check this limit. To solve it, you can edit file /etc/security/limits.conf and add the following lines at the end:

*         hard    nproc     65536
*         soft    nproc      65536

or

myuser         hard    nproc     65536