fix: make workstation tuning conservative and verifiable

.github/workflows/checks.yml

@@ -11,4 +11,4 @@ jobs:
       - run: sudo apt-get update && sudo apt-get install -y shellcheck jq
       - run: bash tests/run.sh
       - name: ShellCheck changed shell scripts
-        run: shellcheck .config/hypr/scripts/wallpaper.sh .config/rofi/scripts/{wifi,clipboard_history,wallpaper}.sh tests/*.sh
+        run: shellcheck .config/hypr/scripts/wallpaper.sh .config/rofi/scripts/{wifi,clipboard_history,wallpaper}.sh scripts/apply-system-optimizations.sh tests/*.sh

README.md

@@ -164,22 +164,18 @@ Existing conflicting configuration files or directories will be safely backed up
 
 ## System optimizations
 
-An automated tuning script is included in `scripts/apply-system-optimizations.sh`. It configures:
-
-- DNF parallel downloads (capped at 2), fastest mirror selection, and default yes prompts.
-- Tuned power profile set to `desktop` for responsive CPU governor scaling.
-- Disables `NetworkManager-wait-online.service` to trim cold boot time.
-- Inotify user watch limit raised to 524,288 for large development projects.
-- Hardware video decode via RPM Fusion `mesa-va-drivers-freeworld` on AMD Radeon GPUs.
-- Disables idle background daemons (`ModemManager`, `thermald`, `rsyslog`, `abrtd`, and `lvm2-monitor`).
-- Installs modern developer CLI tools (`fzf`, `zoxide`, `eza`, `git-delta`, `duf`).
-
-To apply these tweaks:
+The default script changes only the developer file-watch limit:
 
 ```bash
 sudo ./scripts/apply-system-optimizations.sh
 ```
 
+It preserves unrelated sysctl settings and higher watch limits, backs up changed
+files, verifies the kernel value, and restores the previous setting if application
+fails. It does not install packages, alter power profiles, or disable services.
+See [optional system steps](docs/system-tuning.md) for individually verified
+changes and rollback. Previously applied system settings are left in place.
+
 ## Verification
 
 Run `bash tests/run.sh` for shell syntax and isolated regression checks. Tests use

docs/system-tuning.md

@@ -0,0 +1,67 @@
+# Optional workstation changes
+
+## TL;DR
+
+The default script only raises the developer file-watch limit. Apply the steps
+below separately after recording current settings. These commands are for the
+Fedora workstation; they are not automatic optimizations or measured wins.
+
+## DNF preferences
+
+Inspect `/etc/dnf/dnf.conf` and back it up with `sudo cp -a --backup=numbered
+/etc/dnf/dnf.conf /etc/dnf/dnf.conf.before-dotfiles` before editing. Keep
+`max_parallel_downloads=2` as the existing preference until download measurements
+justify another value. `fastestmirror=True` selects by connection latency, not
+throughput. `defaultyes=True` changes the default confirmation choice, not speed.
+For Fedora defaults remove those overrides only after reviewing the file. Verify
+with `dnf --dump-main-config` (check the installed DNF version's help first).
+Restore the saved file to roll back.
+
+Reference: [DNF5 configuration](https://dnf5.readthedocs.io/en/latest/dnf5.conf.5.html).
+
+## Power profile
+
+Run `tuned-adm active` and `tuned-adm verify` in the actual host session. Record the
+active profile before testing another. Keep the current profile by default.
+If testing desktop scaling, first confirm `desktop` appears in `tuned-adm list`,
+then run `sudo tuned-adm profile desktop`; verify and compare responsiveness and
+idle power. Roll back with `sudo tuned-adm profile PREVIOUS_PROFILE`. A file in
+`/etc/tuned` is not proof of live activation; do not disable other power managers
+without understanding the host's integration.
+
+## Services and boot
+
+Measure `systemd-analyze critical-chain` and `systemd-analyze blame` first. Inspect
+`systemctl list-dependencies --reverse NetworkManager-wait-online.service` and
+whether network-dependent mounts/services need it. If demonstrated unnecessary,
+record its enabled state, then use `sudo systemctl disable
+NetworkManager-wait-online.service`; compare subsequent boots. Restore its
+previous enabled state to roll back. Never blindly disable ModemManager, thermald,
+rsyslog, abrtd, or lvm2-monitor; identify actual use and dependencies first.
+Previously disabled services require individual review, not blanket re-enabling.
+
+## AMD hardware video decoding
+
+Inspect `rpm -q mesa-va-drivers mesa-va-drivers-freeworld` and `vainfo`; confirm
+which codecs and driver the running application uses. A package's presence alone
+does not establish active browser decoding. If needed, follow the current
+[RPM Fusion codec instructions](https://rpmfusion.org/Howto/Multimedia) for the
+installed Fedora release. Review a proposed DNF swap interactively; do not add
+repositories or import keys silently. Record the transaction ID and package
+versions. Review `sudo dnf history undo TRANSACTION_ID` to roll back; availability
+of old packages can limit rollback. Do not claim codec acceleration until verified
+in the application.
+
+## Developer tools
+
+Review and run `sudo dnf install fzf zoxide eza git-delta duf` separately. Verify
+with `command -v` for each executable (`delta` is the git-delta executable).
+Record the DNF transaction for rollback; avoid removing pre-existing tools.
+
+## File-watch rollback
+
+On success, the watch-limit helper prints any backup path. Restore that exact
+file and apply just its watch-limit value with `sudo sysctl -w
+fs.inotify.max_user_watches=PREVIOUS_VALUE`. If no file previously existed, remove
+only the newly created workstation file and restore the previously recorded
+kernel value. Do not apply every sysctl file as a shortcut to rollback.

scripts/apply-system-optimizations.sh

@@ -1,63 +1,9 @@
 #!/usr/bin/env bash
+# Apply only the backed-up, verified developer file-watch setting.
 set -euo pipefail
-
-if [ "$EUID" -ne 0 ]; then
-    echo "[-] Please run this script with sudo: sudo ./scripts/apply-system-optimizations.sh"
+if (( EUID != 0 )); then
+    echo 'Run: sudo ./scripts/apply-system-optimizations.sh' >&2
     exit 1
 fi
-
-echo "[+] 1. Configuring DNF for fast mirrors and parallel downloads (max 2)..."
-if ! grep -q "max_parallel_downloads" /etc/dnf/dnf.conf 2>/dev/null; then
-    cat << 'EOF' >> /etc/dnf/dnf.conf
-max_parallel_downloads=2
-fastestmirror=True
-defaultyes=True
-EOF
-    echo "    Done: Added max_parallel_downloads=2, fastestmirror=True, defaultyes=True."
-else
-    sed -i 's/^max_parallel_downloads=.*/max_parallel_downloads=2/' /etc/dnf/dnf.conf
-    echo "    Done: Updated max_parallel_downloads to 2."
-fi
-
-echo "[+] 2. Setting tuned power profile to 'desktop' (optimized for Ryzen desktop workloads)..."
-if command -v tuned-adm >/dev/null 2>&1; then
-    tuned-adm profile desktop
-    echo "    Done: Active tuned profile set to desktop."
-fi
-
-echo "[+] 3. Shaving ~5.6s off boot time (disabling NetworkManager-wait-online.service)..."
-systemctl disable NetworkManager-wait-online.service 2>/dev/null || true
-echo "    Done: NetworkManager-wait-online disabled."
-
-echo "[+] 4. Raising inotify file watch limits for dev projects..."
-cat << 'EOF' > /etc/sysctl.d/99-workstation.conf
-# Raise file watch limits for IDEs, Node, Rust, and Python dev
-fs.inotify.max_user_watches=524288
-EOF
-sysctl -p /etc/sysctl.d/99-workstation.conf
-echo "    Done: inotify watches set to 524288."
-
-echo "[+] 5. Setting up RPM Fusion Free & hardware video acceleration (VA-API freeworld)..."
-if ! dnf repolist | grep -q "rpmfusion-free"; then
-    echo "    Enabling RPM Fusion Free repository..."
-    dnf install -y "https://mirrors.rpmfusion.org/free/fedora/rpmfusion-free-release-$(rpm -E %fedora).noarch.rpm" || true
-fi
-
-if dnf repolist | grep -q "rpmfusion-free"; then
-    echo "    Swapping mesa-va-drivers for freeworld hardware acceleration..."
-    dnf swap -y mesa-va-drivers mesa-va-drivers-freeworld || true
-    echo "    Done: Hardware video acceleration installed."
-fi
-
-echo "[+] 6. Disabling unnecessary background daemons (ModemManager, thermald, rsyslog, abrtd, lvm2-monitor)..."
-systemctl disable --now thermald ModemManager rsyslog abrtd lvm2-monitor 2>/dev/null || true
-echo "    Done: Unnecessary background daemons disabled."
-
-echo "[+] 7. Installing modern developer CLI tools (fzf, zoxide, eza, git-delta, duf)..."
-if dnf install -y fzf zoxide eza git-delta duf; then
-    echo "    Done: Modern developer CLI tools installed."
-else
-    echo "    [!] Warning: Failed to install developer CLI tools. Install manually via 'sudo dnf install fzf zoxide eza git-delta duf'."
-fi
-
-echo "[✓] All system-level performance optimizations applied successfully!"
+python3 "$(dirname "${BASH_SOURCE[0]}")/inotify.py"
+echo 'File-watch setting verified. Other system settings were not changed.'

scripts/inotify.py

@@ -0,0 +1,93 @@
+#!/usr/bin/env python3
+"""Raise the workstation watch limit with preserved settings and rollback on failure."""
+import os
+from pathlib import Path
+import re
+import shutil
+import stat
+import subprocess
+import sys
+import tempfile
+
+KEY = 'fs.inotify.max_user_watches'
+MINIMUM = 524288
+
+
+def apply(config: Path) -> int:
+    """Preserve higher limits, update only KEY, and verify the running kernel.
+
+    Args:
+        config: Sysctl file to update; production uses the fixed workstation path.
+    Returns:
+        The verified effective watch limit.
+    Raises:
+        ValueError: Existing configuration is malformed.
+        OSError: Configuration cannot be safely written.
+        subprocess.CalledProcessError: A sysctl command fails.
+        RuntimeError: The kernel does not report the requested value.
+    """
+    if config.is_symlink():
+        raise ValueError('Refusing to replace a symlinked sysctl file')
+    current = int(subprocess.check_output(['sysctl', '-n', KEY], text=True).strip())
+    original = config.read_text() if config.exists() else ''
+    lines = original.splitlines(keepends=True)
+    pattern = re.compile(r'^\s*-?fs\.inotify\.max_user_watches\s*(?:=\s*|\s+)([^#;]+)')
+    values = [int(match.group(1).strip()) for line in lines if (match := pattern.match(line))]
+    desired = max(MINIMUM, current, *values)
+    # Keep exact formatting when an existing single setting already suffices.
+    if values == [desired]:
+        updated = original
+    else:
+        updated = ''.join(line for line in lines if not pattern.match(line))
+        if updated and not updated.endswith('\n'):
+            updated += '\n'
+        updated += f'{KEY}={desired}\n'
+    backup = None
+    changed = updated != original
+    if changed:
+        config.parent.mkdir(parents=True, exist_ok=True)
+        metadata = config.stat() if config.exists() else None
+        if metadata:
+            fd, name = tempfile.mkstemp(prefix=config.name + '.backup-', dir=config.parent)
+            os.close(fd)
+            backup = Path(name)
+            shutil.copy2(config, backup)
+        fd, name = tempfile.mkstemp(prefix='.' + config.name, dir=config.parent)
+        temporary = Path(name)
+        try:
+            with os.fdopen(fd, 'w') as output:
+                os.fchmod(output.fileno(), stat.S_IMODE(metadata.st_mode) if metadata else 0o644)
+                if metadata:
+                    os.fchown(output.fileno(), metadata.st_uid, metadata.st_gid)
+                output.write(updated)
+                output.flush()
+                os.fsync(output.fileno())
+            os.replace(temporary, config)
+        finally:
+            temporary.unlink(missing_ok=True)
+        if backup:
+            print(f'Previous configuration saved to {backup}')
+    try:
+        if current != desired:
+            subprocess.run(['sysctl', '-w', f'{KEY}={desired}'], check=True)
+        effective = int(subprocess.check_output(['sysctl', '-n', KEY], text=True).strip())
+        if effective != desired:
+            raise RuntimeError(f'Expected {desired} watches, kernel reports {effective}')
+    except (OSError, ValueError, subprocess.CalledProcessError, RuntimeError):
+        if changed:
+            if backup:
+                os.replace(backup, config)
+            else:
+                config.unlink(missing_ok=True)
+        try:
+            subprocess.run(['sysctl', '-w', f'{KEY}={current}'], check=True)
+        except (OSError, subprocess.CalledProcessError) as error:
+            print(f'Could not restore the previous kernel value: {error}', file=sys.stderr)
+        raise
+    return effective
+
+
+if __name__ == '__main__':
+    if os.geteuid() != 0:
+        raise SystemExit('Run through sudo ./scripts/apply-system-optimizations.sh')
+    print(f'Verified watch limit: {apply(Path("/etc/sysctl.d/99-workstation.conf"))}')

tests/run.sh

@@ -4,3 +4,5 @@ set -euo pipefail
 cd "$(dirname "$0")/.."
 while IFS= read -r -d '' script; do bash -n "$script"; done < <(find scripts .config tests -type f -name '*.sh' -print0)
 for test in tests/*.sh; do [[ $test == tests/run.sh ]] || bash "$test"; done
+
+for test in tests/*.py; do [[ ! -f $test ]] || python3 -B "$test"; done

tests/tuning.py

@@ -0,0 +1,68 @@
+"""Check sysctl preservation, verification, and rollback using disposable files."""
+import importlib.util
+from pathlib import Path
+import subprocess
+import tempfile
+import unittest
+from unittest.mock import patch
+
+spec = importlib.util.spec_from_file_location('inotify', Path(__file__).resolve().parents[1] / 'scripts/inotify.py')
+inotify = importlib.util.module_from_spec(spec)
+spec.loader.exec_module(inotify)
+
+class TuningTests(unittest.TestCase):
+    def test_preserves_higher_limits_and_unrelated_settings(self):
+        with tempfile.TemporaryDirectory() as directory:
+            config = Path(directory) / 'workstation.conf'
+            original = '# local comment\nvm.swappiness=80\nfs.inotify.max_user_watches=1048576\n'
+            config.write_text(original)
+            with patch.object(inotify.subprocess, 'check_output', side_effect=['524288', '1048576']), patch.object(inotify.subprocess, 'run') as run:
+                self.assertEqual(inotify.apply(config), 1048576)
+                self.assertEqual(config.read_text(), original)
+                run.assert_called_once_with(['sysctl', '-w', 'fs.inotify.max_user_watches=1048576'], check=True)
+                self.assertEqual(list(Path(directory).glob('*.backup-*')), [])
+
+    def test_updates_once_and_backs_up(self):
+        with tempfile.TemporaryDirectory() as directory:
+            config = Path(directory) / 'workstation.conf'
+            original = '# custom\nvm.swappiness=80\nfs.inotify.max_user_watches = 8192\n'
+            config.write_text(original)
+            with patch.object(inotify.subprocess, 'check_output', return_value='524288'), patch.object(inotify.subprocess, 'run'):
+                inotify.apply(config)
+                first = config.read_text()
+                inotify.apply(config)
+            self.assertIn('vm.swappiness=80', first)
+            backups = list(Path(directory).glob('*.backup-*'))
+            self.assertEqual(len(backups), 1)
+            self.assertEqual(backups[0].read_text(), original)
+
+    def test_failed_apply_restores_file(self):
+        with tempfile.TemporaryDirectory() as directory:
+            config = Path(directory) / 'workstation.conf'
+            original = 'vm.swappiness=80\n'
+            config.write_text(original)
+            failure = subprocess.CalledProcessError(1, 'sysctl')
+            with patch.object(inotify.subprocess, 'check_output', return_value='8192'), patch.object(inotify.subprocess, 'run', side_effect=[failure, None]):
+                with self.assertRaises(subprocess.CalledProcessError):
+                    inotify.apply(config)
+            self.assertEqual(config.read_text(), original)
+
+    def test_failed_verification_removes_new_file(self):
+        with tempfile.TemporaryDirectory() as directory:
+            config = Path(directory) / 'workstation.conf'
+            with patch.object(inotify.subprocess, 'check_output', side_effect=['8192', '8192']), patch.object(inotify.subprocess, 'run'):
+                with self.assertRaises(RuntimeError):
+                    inotify.apply(config)
+            self.assertFalse(config.exists())
+
+    def test_malformed_existing_value_is_not_overwritten(self):
+        with tempfile.TemporaryDirectory() as directory:
+            config = Path(directory) / 'workstation.conf'
+            config.write_text('fs.inotify.max_user_watches=unexpected\n')
+            with patch.object(inotify.subprocess, 'check_output', return_value='8192'), patch.object(inotify.subprocess, 'run') as run:
+                with self.assertRaises(ValueError):
+                    inotify.apply(config)
+                run.assert_not_called()
+
+if __name__ == '__main__':
+    unittest.main()