testsAndMisc/linux_configuration/scripts/system-maintenance/systemd/monitors.slice

[Unit]
Description=Resource-capped slice for user monitoring / status-bar scripts
Documentation=https://www.freedesktop.org/software/systemd/man/systemd.slice.html

[Slice]
# Cap the entire slice at 50% of one CPU and 512 MiB of RAM. If i3blocks or
# any other status-bar tooling enters a fork-storm regime (as was observed
# when polling scripts forked awk/tr/grep/bc every tick), the kernel will
# throttle the slice rather than let it eat the box.
CPUQuota=50%
# MemorySwapMax=0 is required on systems with zram: without it, a cgroup
# hitting MemoryMax thrashes zram instead of being OOM-killed, freezing
# the machine. See .github/skills/oom-prevention/SKILL.md.
MemoryMax=512M
MemorySwapMax=0
TasksMax=256

# Make sure killing the slice reaps every descendant.
[Install]
WantedBy=default.target
i3blocks: eliminate fork-storm with persist mode + zero-fork sysfs reads Resource-usage report showed ~29 cores of average load coming from i3blocks helper scripts forking awk/tr/grep/bc/sensors/nvidia-smi every tick. Rewrite all five hot-path scripts to eliminate forks: - volume.sh: persist mode, blocks on 'pactl subscribe' event stream. No polling, no sleep, no fork per tick. - gpu_monitor.sh: persist mode, single long-lived 'nvidia-smi --loop=5' feeds a bash 'while read' loop. Falls back to /sys for amdgpu. - battery_status.sh: reads /sys/class/power_supply/BAT/ directly. Zero forks; replaces 'acpi \| awk' pipeline. - cpu_monitor.sh: reads /proc/loadavg and k10temp/coretemp /sys/class/hwmon. Zero forks; replaces 'sensors \| awk \| tr' + bc arithmetic. - motherboard_temp.sh: reads nct/it/f71 Super-I/O hwmon node directly. Zero forks. Configure volume + gpu_monitor with interval=persist so i3blocks keeps one long-lived producer each instead of forking per tick. Also add: - kill_stale_recorders.sh -- kill stray ffmpeg x11grab / dotnet-trace / dotnet-monitor processes left running after sessions. - monitors.slice -- resource-capped user slice (CPUQuota=50%, MemoryMax=512M, MemorySwapMax=0 for zram safety, TasksMax=256) to bound future monitoring regressions. - efficient-polling-scripts SKILL -- rules for writing status-bar and polling scripts without forks; fork-pipeline to bash-builtin translation table; verification checklist. Verified live: strace -c on cpu_monitor.sh shows 1 execve / 0 clones; persist producers (pactl subscribe, nvidia-smi --loop) show 0 CPU ticks over a 3s idle sample. Per-invocation timing 1.6-1.9 ms (was 30-80 ms). 2026-04-20 21:54:11 +02:00			`[Unit]`
			`Description=Resource-capped slice for user monitoring / status-bar scripts`
			`Documentation=https://www.freedesktop.org/software/systemd/man/systemd.slice.html`

			`[Slice]`
			`# Cap the entire slice at 50% of one CPU and 512 MiB of RAM. If i3blocks or`
			`# any other status-bar tooling enters a fork-storm regime (as was observed`
			`# when polling scripts forked awk/tr/grep/bc every tick), the kernel will`
			`# throttle the slice rather than let it eat the box.`
			`CPUQuota=50%`
			`# MemorySwapMax=0 is required on systems with zram: without it, a cgroup`
			`# hitting MemoryMax thrashes zram instead of being OOM-killed, freezing`
			`# the machine. See .github/skills/oom-prevention/SKILL.md.`
			`MemoryMax=512M`
			`MemorySwapMax=0`
			`TasksMax=256`

			`# Make sure killing the slice reaps every descendant.`
			`[Install]`
			`WantedBy=default.target`