Read-only: print host IRQ/workqueue/RPS CPU masks compactly (changes nothing)

show-spdk-masks.sh

#!/bin/bash
# Read-only: print current host IRQ / workqueue / RPS CPU masks compactly.
# Changes NOTHING. No arguments, no root strictly required (some files may be
# unreadable without it, shown as '?').
set -uo pipefail

log() { echo "$(date '+%Y-%m-%d %H:%M:%S') $*"; }

compact() {
    # reads mask values on stdin, prints "value (xN)" groups on one line
    sort | uniq -c | awk '{printf "%s%s (x%s)", (NR>1?", ":""), $2, $1} END{print ""}'
}

log "online CPUs: $(cat /sys/devices/system/cpu/online 2>/dev/null || echo '?')"
log "Current masks (read-only):"
printf '  IRQ default : %s\n' "$(cat /proc/irq/default_smp_affinity 2>/dev/null || echo '?')"
printf '  IRQ per-irq : %s\n' "$(cat /proc/irq/[0-9]*/smp_affinity 2>/dev/null | compact)"
printf '  workqueue   : %s\n' "$(cat /sys/devices/virtual/workqueue/cpumask 2>/dev/null || echo 'n/a')"
printf '  wq per-wq   : %s\n' "$(cat /sys/devices/virtual/workqueue/*/cpumask 2>/dev/null | compact)"
rps_now=""
for path in /sys/class/net/*; do
    [ -L "$path" ] || continue
    case "$(readlink "$path")" in *virtual*) continue ;; esac
    rps_now+=$(cat "$path"/queues/rx-*/rps_cpus 2>/dev/null; echo)
done
printf '  RPS         : %s\n' "$(printf '%s' "$rps_now" | grep -v '^$' | compact)"