8.5. Setting Semaphore Parameters

To determine the values of the four described semaphore parameters, run:

cat /proc/sys/kernel/sem
250     32000   32      128

# cat /proc/sys/kernel/sem
250     32000   32      128

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These values represent SEMMSL, SEMMNS, SEMOPM, and SEMMNI.

Alternatively, you can run:

ipcs -ls

# ipcs -ls

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All four described semaphore parameters can be changed in the proc file system without reboot:

echo 250 32000 100 128 > /proc/sys/kernel/sem

# echo 250 32000 100 128 > /proc/sys/kernel/sem

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Alternatively, you can use sysctl(8) to change it:

sysctl -w kernel.sem="250 32000 100 128"

sysctl -w kernel.sem="250 32000 100 128"

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To make the change permanent, 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 100 128" >> /etc/sysctl.conf

echo "kernel.sem=250 32000 100 128" >> /etc/sysctl.conf

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