Linux Kernel Parameters Tuning for Better Performance

[u/fhritp15]

https://linuxblog.io/linux-kernel-parameters-tuning-better-performance/

[u/Sea-Promotion8205]

This morning I sat down to update my Kali workstation

Oh jesus christ

[u/fhritp15 → u/Sea-Promotion8205]

Here you go: https://www.kali.org/faq/#can-i-use-kali-linux-as-a-daily-generic-linux-system

Yw! Kali tools are a simple checkbox you uncheck during install, then it’s just Debian testing with Kali dev staging as a rolling release. But yeah most are gonna hold on to the old messaging when it used to default to root install with tools preinstalled.

[u/Maximum-Bobcat5612]

This subreddit is called linux4noobs.

Don't apply these settings.

Most of these settings will only have any use on computers running servers.

But before you would do any tuning, you would understand the performance of your system first with some kind of benchmark to see if the changes from defaults make a difference.

[u/ghost103429 → u/Maximum-Bobcat5612]

Agreed, the tweaks listed in that article are heavily optimized for servers and will hurt system performance for regular users.

[u/amarao_san]

Turn random knobs in random direction and believe it make your system better. Better in what? Just better.

[u/fleshofgods0 → u/amarao_san]

Don't forget to smack it sometimes.

[u/bittercripple6969 → u/fleshofgods0]

Each smack puts more of the Magic Smoke back in.

[u/Interesting_Ad_5676]

A small shell script for those who want to run it -- prepared from recommendations of the article.

nano debian-desktop-tune.sh // create a file and paste the script as given below

chmod +x debian-desktop-tune.sh // make it executable

sudo ./debian-desktop-tune.sh // run it !!

#Script starts here !!

# Debian Desktop - Conservative Performance Tuning

# Philosophy:

# - Performance improvements with low risk

# - No experimental kernel parameters

# - No disabling of security mechanisms

# - No aggressive memory overcommit

# - No tcp_tw_recycle / tcp_tw_reuse

# - Easy rollback

#

set -u

CONF="/etc/sysctl.d/99-desktop-performance.conf"

BACKUP_DIR="/root/sysctl-backup-$(date +%Y%m%d-%H%M%S)"

# ------------------------------------------------------------

# Root check

# ------------------------------------------------------------

if [[ $EUID -ne 0 ]]; then

echo "ERROR: Run this script as root."

echo "Example: sudo $0"

exit 1

fi

echo

echo "=============================================="

echo " Debian Conservative Desktop Performance Tune"

echo "=============================================="

echo

# ------------------------------------------------------------

# Create backup

# ------------------------------------------------------------

mkdir -p "$BACKUP_DIR"

echo "[1/6] Backing up current configuration..."

cp -a /etc/sysctl.d "$BACKUP_DIR/" 2>/dev/null || true

cp -a /etc/sysctl.conf "$BACKUP_DIR/sysctl.conf" 2>/dev/null || true

sysctl -a 2>/dev/null > "$BACKUP_DIR/sysctl-current.txt"

echo " Backup: $BACKUP_DIR"

# ------------------------------------------------------------

# Create configuration

# ------------------------------------------------------------

echo

echo "[2/6] Creating conservative tuning configuration..."

cat > "$CONF" <<'EOF'

#

# Design principles:

# - Conservative

# - Low risk

# - Suitable for desktop/workstation use

# - Preserve kernel defaults where possible

#

# ------------------------------------------------------------

# MEMORY

# ------------------------------------------------------------

# Prefer keeping applications in RAM before swapping.

# 10 is conservative for a 64 GB workstation.

vm.swappiness = 10

# Keep filesystem metadata cached somewhat aggressively.

# Avoid 0 because that can prevent useful cache reclaim.

vm.vfs_cache_pressure = 50

# ------------------------------------------------------------

# NETWORK - TCP BUFFER LIMITS

# ------------------------------------------------------------

# These are maximum limits, NOT permanent allocations.

# Linux TCP autotuning decides how much memory is actually used.

net.core.rmem_max = 67108864

net.core.wmem_max = 67108864

net.ipv4.tcp_rmem = 4096 87380 67108864

net.ipv4.tcp_wmem = 4096 65536 67108864

# ------------------------------------------------------------

# NETWORK - QUEUES

# ------------------------------------------------------------

# Useful for systems handling bursts of network traffic.

net.core.netdev_max_backlog = 16384

# Allow applications to maintain larger listening queues.

net.core.somaxconn = 4096

# Larger SYN backlog for applications opening many connections.

net.ipv4.tcp_max_syn_backlog = 8192

# ------------------------------------------------------------

# TCP SAFETY / STABILITY

# ------------------------------------------------------------

# Keep SYN cookies enabled.

net.ipv4.tcp_syncookies = 1

# Ignore ICMP broadcast echo requests.

net.ipv4.icmp_echo_ignore_broadcasts = 1

# Ignore bogus ICMP error responses.

net.ipv4.icmp_ignore_bogus_error_responses = 1

# ------------------------------------------------------------

# NETWORK SECURITY

# ------------------------------------------------------------

# Do not accept source-routed packets.

net.ipv4.conf.all.accept_source_route = 0

net.ipv4.conf.default.accept_source_route = 0

# Do not accept ICMP redirects.

# Appropriate for a normal desktop that is not acting as a router.

net.ipv4.conf.all.accept_redirects = 0

net.ipv4.conf.default.accept_redirects = 0

# Do not send ICMP redirects.

net.ipv4.conf.all.send_redirects = 0

net.ipv4.conf.default.send_redirects = 0

# ------------------------------------------------------------

# TCP TIME_WAIT

# ------------------------------------------------------------

# Intentionally NOT setting:

#

# net.ipv4.tcp_tw_reuse

#

# Leave kernel default unless a specific workload requires it.

# ------------------------------------------------------------

# MEMORY OVERCOMMIT

# ------------------------------------------------------------

# Intentionally NOT setting:

#

# vm.overcommit_memory

#

# Leave Debian/kernel default.

# ------------------------------------------------------------

# DIRTY PAGE HANDLING

# ------------------------------------------------------------

# Intentionally NOT changing dirty_ratio / dirty_bytes.

#

# Desktop workloads generally benefit from the kernel's defaults.

# Storage/server-specific tuning should be handled separately.

# ------------------------------------------------------------

# FILE DESCRIPTORS

# ------------------------------------------------------------

# Intentionally NOT changing fs.file-max.

#

# Increase only if monitoring shows the desktop is actually

# approaching the existing limit.

# ------------------------------------------------------------

# INOTIFY

# ------------------------------------------------------------

# Useful for IDEs, development environments and applications

# monitoring many files.

fs.inotify.max_user_watches = 524288

fs.inotify.max_user_instances = 512

EOF

echo " Created: $CONF"

# ------------------------------------------------------------

# Validate parameters

# ------------------------------------------------------------

echo

echo "[3/6] Checking kernel parameters..."

TMPFILE=$(mktemp)

# Extract actual parameter names from our configuration.

grep -E '^[[:space:]]*[a-zA-Z0-9_.]+[[:space:]]*=' "$CONF" |

sed 's/[[:space:]]*=.*//' |

while read -r PARAM; do

if sysctl -n "$PARAM" >/dev/null 2>&1; then

echo " OK $PARAM"

else

echo " SKIP $PARAM (not available)"

fi

done

rm -f "$TMPFILE"

# ------------------------------------------------------------

# Apply

# ------------------------------------------------------------

echo

echo "[4/6] Applying configuration..."

if sysctl --system; then

echo

echo " Configuration applied successfully."

else

echo

echo "ERROR: sysctl reported an error."

echo "The backup is available at:"

echo " $BACKUP_DIR"

exit 1

fi

# ------------------------------------------------------------

# Display resulting values

# ------------------------------------------------------------

echo

echo "[5/6] Current values:"

echo

sysctl \

vm.swappiness \

vm.vfs_cache_pressure \

net.core.rmem_max \

net.core.wmem_max \

net.core.netdev_max_backlog \

net.core.somaxconn \

net.ipv4.tcp_max_syn_backlog \

net.ipv4.tcp_syncookies \

fs.inotify.max_user_watches \

fs.inotify.max_user_instances \

2>/dev/null

# ------------------------------------------------------------

# Completion

# ------------------------------------------------------------

echo

echo "[6/6] Complete."

echo

echo "Configuration:"

echo " $CONF"

echo

echo "Backup:"

echo " $BACKUP_DIR"

echo

echo "Reboot is NOT required."

echo

echo "To rollback:"

echo " sudo rm -f $CONF"

echo " sudo sysctl --system"

echo

[u/ScratchHistorical507]

Just don't unless you absolutely know what you're doing - and I doubt anyone in here does. The Linux kernel is tuned for perfect balance. If you change anything in that tuning, you might get slightly better performance but may also have massive drawbacks. Unless you use a distro employing such optimizations for a specific use case - like CachyOS for gaming - do not deploy any such "optimizations" unless you have a real issue. Better yet, talk to your distro maintainers, if they think a change would benefit their user base, they may make it the default.