4f35df1781
🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
87 lines
2.5 KiB
Bash
Executable File
87 lines
2.5 KiB
Bash
Executable File
#!/bin/bash
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# Apply CPU cores defaults to cmdline.txt (fallback for manual installations)
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# Used by dangerous-pi-cpu-cores.service
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#
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# NOTE: When using the official pi-gen image, maxcpus is already set during build.
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# This script only runs as a fallback for manual installations.
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#
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# On Pi Zero 2 W (and other ARM devices), CPU hotplug via sysfs does NOT work.
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# Instead, we use the maxcpus=N kernel parameter in cmdline.txt.
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# This script sets the default maxcpus for Pi Zero 2 W if not already configured.
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LOG_TAG="dangerous-pi-cpu-cores"
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log() {
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logger -t "$LOG_TAG" "$1"
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echo "$1"
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}
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# Find cmdline.txt (location varies by Pi OS version)
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find_cmdline() {
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if [ -f /boot/firmware/cmdline.txt ]; then
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echo "/boot/firmware/cmdline.txt"
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elif [ -f /boot/cmdline.txt ]; then
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echo "/boot/cmdline.txt"
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else
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echo ""
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fi
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}
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CMDLINE_FILE=$(find_cmdline)
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if [ -z "$CMDLINE_FILE" ]; then
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log "ERROR: Could not find cmdline.txt"
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exit 1
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fi
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# Check if maxcpus is already configured
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if grep -q "maxcpus=" "$CMDLINE_FILE"; then
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CURRENT=$(grep -o 'maxcpus=[0-9]*' "$CMDLINE_FILE" | cut -d= -f2)
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log "maxcpus already configured: $CURRENT cores"
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exit 0
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fi
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# Determine default cores based on Pi model
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get_default_cores() {
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local model=""
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local total_cores=$(nproc --all)
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if [ -f /proc/device-tree/model ]; then
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model=$(cat /proc/device-tree/model | tr -d '\0')
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fi
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# Pi Zero 2 W has 4 cores but should default to 2 for thermal management
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if echo "$model" | grep -q "Pi Zero 2"; then
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echo 2
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# Single-core Pis - no need to set maxcpus
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elif echo "$model" | grep -q "Pi Zero W\|Pi Zero$\|Pi 1\|Pi Model A\|Pi Model B"; then
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echo "$total_cores" # Return total (no restriction needed)
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# All other multi-core Pis use all cores by default
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else
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echo "$total_cores"
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fi
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}
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DEFAULT_CORES=$(get_default_cores)
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TOTAL_CORES=$(nproc --all)
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# Only set maxcpus if we want fewer than total cores
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if [ "$DEFAULT_CORES" -lt "$TOTAL_CORES" ]; then
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log "Setting default maxcpus=$DEFAULT_CORES for this device"
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# Backup original
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cp "$CMDLINE_FILE" "${CMDLINE_FILE}.bak"
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# Append maxcpus to cmdline
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CURRENT_CMDLINE=$(cat "$CMDLINE_FILE" | tr -d '\n')
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echo "$CURRENT_CMDLINE maxcpus=$DEFAULT_CORES" > "${CMDLINE_FILE}.new"
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mv "${CMDLINE_FILE}.new" "$CMDLINE_FILE"
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log "Updated $CMDLINE_FILE with maxcpus=$DEFAULT_CORES"
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log "NOTE: This will take effect on next reboot"
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else
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log "No maxcpus restriction needed (using all $TOTAL_CORES cores)"
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fi
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exit 0
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