Extending cpuset to include user processes

[Snoopy8]

Further adventures with cpuset; information may be useful for the further extension of cpuset within SnakeOil.

Have a 4 CPU Intel NUC and used this script for my mpd setup
 

Code:

#
# set up cpusets
#
cset set -c 0 -s system
cset set -c 1 -s irq --cpu_exclusive
cset set -c 2 -s player --cpu_exclusive
cset set -c 3 -s server --cpu_exclusive
#
# move music server and player threads
#
cset proc --move --toset=player --pid $(pgrep mpd) --threads
cset proc --move --toset=server --pid $(pgrep camilladsp) --threads
#
# move all unbound kernel threads to system cpuset, and usb irq to irq cpuset
#
cset proc -k -f root -t system
cset proc --move --toset=irq --pid $(pgrep irq/123-xhci_hc) --kthread --force

Mpd and CamiilaDSP were moved to individual CPUs using a command similar to this:
"cset proc --move --toset=player --pid $(pgrep mpd) --threads".

Ideally, to reduce latency, IRQs should be on a different CPU to the music threads. Some IRQs were bound to CPUs, but many of the IRQs were moved using the following:

1. Edited /etc/default/irqbalance and set IRQBALANCE_BANNED_CPUS=C  (hex mask value, run in CPUs 0,1 not in CPUs 2,3). 
   
2. Alternately, disabled or uninstalled IRQBalance and more IRQs will run on the first CPU (CPU0)
   
3. Used "cset proc -k -f root -t system" to move some more IRQs
   
4. Used "cset proc --move --toset=irq --pid $(pgrep irq/123-xhci_hc) --kthread --force" to move USB IRQ to its own CPU.
   

Some music threads could not be moved eg. Minimserver is Java based. These music threads should be started within a cpuset using a command similar to this:
"cset proc -s server -e /bin/bash -- /var/www/players/minimserver/start.sh"

Some useful information on cpusets
https://documentation.suse.com/sle-rt/15...model.html
https://documentation.suse.com/sle-rt/15...puset.html