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server-config/tests/xmrig-auto-pause.nix
Simon Gardling d48f27701f xmrig-auto-pause: add hysteresis to prevent stop/start thrashing
xmrig's RandomX pollutes the L3 cache, making other processes appear
~3-8% busier. With a single 5% threshold for both stopping and
resuming, the script oscillates: start xmrig -> cache pressure
inflates CPU -> stop xmrig -> CPU drops -> restart -> repeat.

Split into CPU_STOP_THRESHOLD (15%) and CPU_RESUME_THRESHOLD (5%).
The stop threshold sits above xmrig's indirect pressure, so only
genuine workloads trigger a pause. The resume threshold confirms the
system is truly idle before restarting.
2026-04-07 01:09:06 -04:00

207 lines
7.6 KiB
Nix

{
pkgs,
...
}:
let
script = ../services/monero/xmrig-auto-pause.py;
python = pkgs.python3;
in
pkgs.testers.runNixOSTest {
name = "xmrig-auto-pause";
nodes.machine =
{ pkgs, ... }:
{
environment.systemPackages = [
pkgs.python3
pkgs.procps
];
# Mock xmrig as a nice'd sleep process that can be stopped/started.
systemd.services.xmrig = {
description = "Mock xmrig miner";
serviceConfig = {
ExecStart = "${pkgs.coreutils}/bin/sleep infinity";
Type = "simple";
Nice = 19;
};
wantedBy = [ "multi-user.target" ];
};
};
testScript = ''
import time
PYTHON = "${python}/bin/python3"
SCRIPT = "${script}"
# Tuned for test VMs (1-2 cores).
# POLL_INTERVAL=1 keeps detection latency low.
# GRACE_PERIOD=5 is long enough to verify "stays stopped" but short
# enough that the full test completes in reasonable time.
# CPU_STOP_THRESHOLD=20 catches a busy-loop on a 1-2 core VM (50-100%)
# without triggering from normal VM noise.
# CPU_RESUME_THRESHOLD=10 is the idle cutoff for a 1-2 core VM.
POLL_INTERVAL = "1"
GRACE_PERIOD = "5"
CPU_STOP_THRESHOLD = "20"
CPU_RESUME_THRESHOLD = "10"
STARTUP_COOLDOWN = "4"
STATE_DIR = "/tmp/xap-state"
def start_cpu_load(name):
"""Start a non-nice CPU burn as a transient systemd unit."""
machine.succeed(
f"systemd-run --unit={name} --property=Type=exec "
f"bash -c 'while true; do :; done'"
)
def stop_cpu_load(name):
machine.succeed(f"systemctl stop {name}")
def start_monitor(unit_name):
"""Start the auto-pause monitor as a transient unit."""
machine.succeed(
f"systemd-run --unit={unit_name} "
f"--setenv=POLL_INTERVAL={POLL_INTERVAL} "
f"--setenv=GRACE_PERIOD={GRACE_PERIOD} "
f"--setenv=CPU_STOP_THRESHOLD={CPU_STOP_THRESHOLD} "
f"--setenv=CPU_RESUME_THRESHOLD={CPU_RESUME_THRESHOLD} "
f"--setenv=STARTUP_COOLDOWN={STARTUP_COOLDOWN} "
f"--setenv=STATE_DIR={STATE_DIR} "
f"{PYTHON} {SCRIPT}"
)
# Monitor needs two consecutive polls to compute a CPU delta.
time.sleep(3)
# Monitor needs two consecutive polls to compute a CPU delta.
time.sleep(3)
start_all()
machine.wait_for_unit("multi-user.target")
machine.wait_for_unit("xmrig.service")
machine.succeed(f"mkdir -p {STATE_DIR}")
with subtest("Start auto-pause monitor"):
start_monitor("xmrig-auto-pause")
with subtest("xmrig stays running while system is idle"):
machine.succeed("systemctl is-active xmrig")
with subtest("xmrig stopped when CPU load appears"):
start_cpu_load("cpu-load")
machine.wait_until_fails("systemctl is-active xmrig", timeout=20)
with subtest("xmrig remains stopped during grace period after load ends"):
stop_cpu_load("cpu-load")
# Load just stopped. Grace period is 5s. Check at 2s well within.
time.sleep(2)
machine.fail("systemctl is-active xmrig")
with subtest("xmrig resumes after grace period expires"):
# Already idle since previous subtest. Grace period (5s) plus
# detection delay (~2 polls) plus startup cooldown (4s) means
# xmrig should restart within ~12s.
machine.wait_until_succeeds("systemctl is-active xmrig", timeout=20)
with subtest("Intermittent load does not cause flapping"):
# First load stop xmrig
start_cpu_load("cpu-load-1")
machine.wait_until_fails("systemctl is-active xmrig", timeout=20)
stop_cpu_load("cpu-load-1")
# Brief idle gap shorter than grace period
time.sleep(2)
# Second load arrives before grace period expires
start_cpu_load("cpu-load-2")
time.sleep(3)
# xmrig must still be stopped
machine.fail("systemctl is-active xmrig")
stop_cpu_load("cpu-load-2")
machine.wait_until_succeeds("systemctl is-active xmrig", timeout=20)
with subtest("Sustained load keeps xmrig stopped"):
start_cpu_load("cpu-load-3")
machine.wait_until_fails("systemctl is-active xmrig", timeout=20)
# Stay busy longer than the grace period to prove continuous
# activity keeps xmrig stopped indefinitely.
time.sleep(8)
machine.fail("systemctl is-active xmrig")
stop_cpu_load("cpu-load-3")
machine.wait_until_succeeds("systemctl is-active xmrig", timeout=20)
with subtest("External restart detected and re-stopped under load"):
# Put system under load so auto-pause stops xmrig.
start_cpu_load("cpu-load-4")
machine.wait_until_fails("systemctl is-active xmrig", timeout=20)
# Something external starts xmrig while load is active.
# The script should detect this and re-stop it.
machine.succeed("systemctl start xmrig")
machine.succeed("systemctl is-active xmrig")
machine.wait_until_fails("systemctl is-active xmrig", timeout=20)
stop_cpu_load("cpu-load-4")
machine.wait_until_succeeds("systemctl is-active xmrig", timeout=20)
# --- State persistence and crash recovery ---
machine.succeed("systemctl stop xmrig-auto-pause")
with subtest("xmrig recovers after crash during startup cooldown"):
machine.succeed(f"rm -rf {STATE_DIR} && mkdir -p {STATE_DIR}")
start_monitor("xmrig-auto-pause-crash")
# Load -> xmrig stops
start_cpu_load("cpu-crash")
machine.wait_until_fails("systemctl is-active xmrig", timeout=20)
# End load -> xmrig restarts after grace period
stop_cpu_load("cpu-crash")
machine.wait_until_succeeds("systemctl is-active xmrig", timeout=30)
# Kill xmrig immediately simulates crash during startup cooldown.
# The script should detect the failure when cooldown expires and
# re-enter the retry cycle.
machine.succeed("systemctl kill --signal=KILL xmrig")
machine.wait_until_fails("systemctl is-active xmrig", timeout=5)
# After cooldown + grace period + restart, xmrig should be back.
machine.wait_until_succeeds("systemctl is-active xmrig", timeout=30)
machine.succeed("systemctl stop xmrig-auto-pause-crash")
machine.succeed("systemctl reset-failed xmrig.service || true")
machine.succeed("systemctl start xmrig")
machine.wait_for_unit("xmrig.service")
with subtest("Script restart preserves pause state"):
machine.succeed(f"rm -rf {STATE_DIR} && mkdir -p {STATE_DIR}")
start_monitor("xmrig-auto-pause-persist")
# Load -> xmrig stops
start_cpu_load("cpu-persist")
machine.wait_until_fails("systemctl is-active xmrig", timeout=20)
# Kill the monitor while xmrig is paused (simulates script crash)
machine.succeed("systemctl stop xmrig-auto-pause-persist")
# State file must exist the monitor persisted the pause flag
machine.succeed(f"test -f {STATE_DIR}/paused")
# Start a fresh monitor instance (reads state file on startup)
start_monitor("xmrig-auto-pause-persist2")
# End load the new monitor should pick up the paused state
# and restart xmrig after the grace period
stop_cpu_load("cpu-persist")
machine.wait_until_succeeds("systemctl is-active xmrig", timeout=30)
# State file should be cleaned up after successful restart
machine.fail(f"test -f {STATE_DIR}/paused")
machine.succeed("systemctl stop xmrig-auto-pause-persist2")
'';
}