The semaphores are counters which are used to provide synchronization between processes or between threads within a process for shared resources like shared memories.
To see all semaphore settings, run:
# cat /proc/sys/kernel/sem 250 32000 32 128These values represent SEMMSL, SEMMNS, SEMOPM, and SEMMNI.
Also, you can use the
# ipcs -ls ------ Semaphore Limits -------- max number of arrays = 128 max semaphores per array = 250 max semaphores system wide = 32000 max ops per semop call = 32 semaphore max value = 32767
To permanently change the values of the four semaphore parameters, add or change the
following line in the file:
/etc/sysctl.conf. This file is used during the boot process.
# echo "kernel.sem=250 32000 100 1024" >> /etc/sysctl.conf