[LAU] System Configuration: kernel, CPU frequency, hardware timers

[Kevin Cosgrove]

Hi folks,

Back in 2012 I scripted some post-installation customization for when I
would build a new Linux machine. I suspect that all of what I did is no
longer needed for today's systems. I'm writing to see if someone can
confirm that.

What I did came from these links:

https://wiki.linuxaudio.org/wiki/system_configuration#the_kernel
https://wiki.linuxaudio.org/wiki/system_configuration#cpu_frequency_scaling
https://wiki.linuxaudio.org/wiki/system_configuration#hardware_timers

My new system runs the 4.17.17 kernel along with the rest of Fedora-27.

What do you think? Do I need to taylor the new machine in the above ways?

Thanks!


P.S.:  My script is below, for the curious.

#!/bin/sh

# $Id: 36-linux_musicians,v 1.4 2012/11/16 05:56:14 kevinc Exp $

DATE=`date +%F-%T`

# http://wiki.linuxmusicians.com/doku.php?id=system_configuration#the_kernel
sudo cp /etc/default/grub /etc/default/grub-${DATE}
sudo cp /boot/grub2/grub.cfg /boot/grub2/grub.cfg-${DATE}
# cp /etc/default/grub grub
sudo perl -p -i -e 's/(^GRUB_CMDLINE_LINUX=\"nomodeset.*rhgb) quiet$\"/$1
quiet threadirqs\"/' /etc/default/grub
sudo /sbin/grub2-mkconfig -o /boot/grub2/grub.cfg

#
http://wiki.linuxmusicians.com/doku.php?id=system_configuration#cpu_frequency_scaling
# echo -n performance \
#   | sudo tee /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor
sudo touch /etc/rc.d/rc.local
cp /etc/rc.d/rc.local rc.local_cpufreq
cat << EOF >> rc.local_cpufreq
#!/bin/sh

for cpu in /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor
do
echo -n performance > \$cpu
done
echo 3072 > /sys/class/rtc/rtc0/max_user_freq
EOF
sudo cp rc.local_cpufreq /etc/rc.d/rc.local
sudo chmod 755 /etc/rc.d/rc.local

#
http://wiki.linuxmusicians.com/doku.php?id=system_configuration#hardware_timers
/bin/rm -f 40-timer-permissions.rules
cat << EOF > 40-timer-permissions.rules
KERNEL=="rtc0", GROUP="audio"
KERNEL=="hpet", GROUP="audio"
EOF
sudo cp 40-timer-permissions.rules /etc/udev/rules.d/
sudo chmod 644 /etc/udev/rules.d/40-timer-permissions.rules

cat << EOF > 60-max-user-freq.conf
# High Precision Event Timer for performance audio/MIDI
dev.hpet.max-user-freq=3072
EOF
sudo cp 60-max-user-freq.conf /etc/sysctl.d/
sudo chmod 644 /etc/sysctl.d/60-max-user-freq.conf

cat << EOF > 60-vm.swappiness.conf
# Delay start of use of swap partitions
vm.swappiness = 10
EOF
sudo cp 60-vm.swappiness.conf /etc/sysctl.d/
sudo chmod 644 /etc/sysctl.d/60-vm.swappiness.conf

cat << EOF > 93-audio_limits.conf
# Increase priority of audio applications
# # maximum realtime priority
@audio - rtprio 90
# maximum locked-in-memory address space (KB)
@audio - memlock 2000000
EOF
sudo cp 93-audio_limits.conf /etc/security/limits.d/
sudo chmod 644 /etc/security/limits.d/93-audio_limits.conf

exit
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