[Unit]
Description=JACK2 Audio Server
After=sound.target network.target
Wants=sound.target

[Service]
Type=simple
User=pi
Group=audio
Environment=JACK_NO_AUDIO_RESERVATION=1
Environment=JACK_PROMISCUOUS_SERVER=1

# Real-time scheduling
LimitRTPRIO=99
LimitMEMLOCK=infinity
LimitNICE=-20

# CPU affinity — pin JACK server to audio cores 1-3
CPUAffinity=1-3

# I/O scheduling — realtime class
IOSchedulingClass=realtime
IOSchedulingPriority=0

# JACK daemon command
ExecStart=/usr/bin/jackd \
    -P 70 \
    -t 2000 \
    -d alsa \
    -d hw:USB \
    -r 48000 \
    -p 128 \
    -n 3 \
    -M \
    -X seq \
    -S

# Restart on crash (but not on clean shutdown)
Restart=on-failure
RestartSec=2

[Install]
WantedBy=multi-user.target