FASE 1: Switch ZRAM to zstd, disable zswap

- ZRAM compression: lzo-rle → zstd (better 1:3 ratio vs 1:2.5, saves
  ~50MB more RAM on 512MB ZRAM at cost of slightly more CPU)
- Add zswap.enabled=0 to kernel cmdline (zswap intercepts before ZRAM,
  preventing efficient compressed swap)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

projects/ArchR/devices/RK3326/options

@@ -36,7 +36,7 @@
     KERNEL_MAKE_EXTRACMD=" $(get_kernel_make_extracmd)"
 
   # Kernel cmdline
-    EXTRA_CMDLINE="quiet console=ttyS2,1500000 console=tty0 loglevel=0 vt.global_cursor_default=0 consoleblank=0 net.ifnames=0 systemd.show_status=false mitigations=off audit=0 nowatchdog threadirqs loop.max_loop=16"
+    EXTRA_CMDLINE="quiet console=ttyS2,1500000 console=tty0 loglevel=0 vt.global_cursor_default=0 consoleblank=0 net.ifnames=0 systemd.show_status=false mitigations=off audit=0 nowatchdog threadirqs zswap.enabled=0 loop.max_loop=16"
 
   # Bootloader to use (syslinux / u-boot)
     BOOTLOADER="u-boot"
@@ -76,7 +76,7 @@
     DEBUG_TTY="/dev/ttyS2"
 
   # ZRAM Algorithm
-    ZRAM_COMPRESSION_ALGO="lzo-rle"
+    ZRAM_COMPRESSION_ALGO="zstd"
 
   # ZRAM Size
     ZRAM_SWAP_SIZE="512"

tools/bench.sh

@@ -0,0 +1,103 @@
+#!/bin/bash
+# ArchR Performance Benchmark Script
+# Run on device: bash /flash/bench.sh <scenario> [duration_seconds]
+# Results saved to /storage/bench-results/
+
+DURATION=${2:-60}
+RESULTS_DIR="/storage/bench-results/$(date +%Y%m%d-%H%M%S)-${1:-general}"
+mkdir -p "$RESULTS_DIR"
+
+echo "========================================"
+echo "  ArchR Benchmark: ${1:-general}"
+echo "  Duration: ${DURATION}s"
+echo "  Output: $RESULTS_DIR"
+echo "========================================"
+
+# Metadata
+cat > "$RESULTS_DIR/meta.json" << METAEOF
+{
+  "timestamp": "$(date -Iseconds)",
+  "kernel": "$(uname -r)",
+  "distro": "$(grep ^NAME /etc/os-release | cut -d= -f2)",
+  "cpu_governor": "$(cat /sys/devices/system/cpu/cpufreq/policy0/scaling_governor 2>/dev/null)",
+  "gpu_governor": "$(cat /sys/class/devfreq/ff400000.gpu/governor 2>/dev/null)",
+  "dmc_governor": "$(cat /sys/class/devfreq/dmc/governor 2>/dev/null)",
+  "mem_available_kb": $(grep MemAvailable /proc/meminfo | awk '{print $2}'),
+  "cma_total_kb": $(grep CmaTotal /proc/meminfo | awk '{print $2}'),
+  "cma_free_kb": $(grep CmaFree /proc/meminfo | awk '{print $2}'),
+  "zram_algo": "$(cat /sys/block/zram0/comp_algorithm 2>/dev/null | tr -d '[]')",
+  "swap": "$(swapon --show --noheadings 2>/dev/null | head -1)",
+  "swappiness": $(sysctl -n vm.swappiness 2>/dev/null),
+  "vfs_cache_pressure": $(sysctl -n vm.vfs_cache_pressure 2>/dev/null),
+  "temperature_start": $(cat /sys/class/thermal/thermal_zone0/temp 2>/dev/null),
+  "sd_model": "$(cat /sys/block/mmcblk0/device/name 2>/dev/null)",
+  "scenario": "${1:-general}"
+}
+METAEOF
+
+# PSI monitoring (background)
+echo "Starting PSI monitoring..."
+(
+  while true; do
+    echo "$(date +%s.%N) $(cat /proc/pressure/cpu 2>/dev/null | head -1) $(cat /proc/pressure/memory 2>/dev/null | head -1) $(cat /proc/pressure/io 2>/dev/null | head -1)"
+    sleep 1
+  done
+) > "$RESULTS_DIR/psi.log" &
+PSI_PID=$!
+
+# Frequency + temperature monitoring (background)
+echo "Starting freq/temp monitoring..."
+(
+  while true; do
+    CPU_FREQ=$(cat /sys/devices/system/cpu/cpufreq/policy0/scaling_cur_freq 2>/dev/null)
+    GPU_FREQ=$(cat /sys/class/devfreq/ff400000.gpu/cur_freq 2>/dev/null)
+    DMC_FREQ=$(cat /sys/class/devfreq/dmc/cur_freq 2>/dev/null)
+    TEMP=$(cat /sys/class/thermal/thermal_zone0/temp 2>/dev/null)
+    MEM=$(grep MemAvailable /proc/meminfo | awk '{print $2}')
+    echo "$(date +%s.%N) cpu=$CPU_FREQ gpu=$GPU_FREQ dmc=$DMC_FREQ temp=$TEMP mem=$MEM"
+    sleep 1
+  done
+) > "$RESULTS_DIR/freq-therm.log" &
+FREQ_PID=$!
+
+# vmstat monitoring
+vmstat 1 $DURATION > "$RESULTS_DIR/vmstat.log" &
+VMSTAT_PID=$!
+
+# dmesg monitoring
+dmesg -w > "$RESULTS_DIR/dmesg.log" 2>/dev/null &
+DMESG_PID=$!
+
+echo ""
+echo "Monitors running. Now launch your game/emulator."
+echo "Press Ctrl+C after ${DURATION}s or when done testing."
+echo ""
+
+# Wait
+sleep $DURATION 2>/dev/null || true
+
+# Cleanup
+kill $PSI_PID $FREQ_PID $VMSTAT_PID $DMESG_PID 2>/dev/null
+wait 2>/dev/null
+
+# Generate summary
+TEMP_END=$(cat /sys/class/thermal/thermal_zone0/temp 2>/dev/null)
+MEM_END=$(grep MemAvailable /proc/meminfo | awk '{print $2}')
+
+cat > "$RESULTS_DIR/summary.json" << SUMEOF
+{
+  "duration_s": $DURATION,
+  "temperature_end": $TEMP_END,
+  "mem_available_end_kb": $MEM_END,
+  "psi_samples": $(wc -l < "$RESULTS_DIR/psi.log"),
+  "freq_samples": $(wc -l < "$RESULTS_DIR/freq-therm.log")
+}
+SUMEOF
+
+echo ""
+echo "========================================"
+echo "  Benchmark complete!"
+echo "  Results: $RESULTS_DIR"
+echo "  Files: $(ls $RESULTS_DIR | wc -l)"
+echo "========================================"
+ls -lh "$RESULTS_DIR"