Japanese article
はじめに
ネットワークパフォーマンスチューニング
ツール
仕様
-
メモリ・バッファ設定
net.core.rmem_max/wmem_max: ソケット受信/送信バッファの最大サイズ
tcp_rmem/tcp_wmem: TCP受信/送信バッファサイズ（最小/デフォルト/最大）
初期値: rmem_max/wmem_max = 212KB (212,992 bytes)
推奨値: 12MB以上（4GBメモリなら16MB推奨）
設定値: 16MB (16,777,216 bytes) -
TCP最適化
tcp_fastopen: TCP Fast Open（接続高速化）
tcp_keepalive_probes: 接続維持のプローブ回数
初期値: tcp_wmem最大値 = 4MB (4,194,304), tcp_rmem最大値 = 6MB (6,291,456)
推奨値: 16MB以上
設定値: 16MB (16,777,216) -
TCP設定
tcp_congestion_control: 輻輳制御アルゴリズム
初期値: cubic, fastopen=1, keepalive_probes=9
推奨値: westwood, fastopen=3, keepalive_probes=3
設定値: cubic, fastopen=3, keepalive_probes=3（westwoodは利用不可） -
コネクション追跡
nf_conntrack_max: 同時接続数の上限
netdev_max_backlog: ネットワークデバイスのキューサイズ
somaxconn: リスニングキューの最大サイズ
初期値: nf_conntrack_max=65,536, netdev_max_backlog=1,000, somaxconn=4,096
推奨値: 131,072接続以上
設定値: nf_conntrack_max=262,144, netdev_max_backlog=5,000, somaxconn=16,384
設定
#!/bin/sh
TMP=/tmp/aios
mkdir -p "$TMP"
cat > "$TMP/dynamic-network-optimizer.sh" << 'SCRIPT_END'
#!/bin/sh
set -e
CONFIG_FILE="/etc/sysctl.d/99-network-optimization-auto.conf"
RED='\033[0;31m'
GREEN='\033[0;32m'
YELLOW='\033[1;33m'
BLUE='\033[0;34m'
CYAN='\033[0;36m'
MAGENTA='\033[0;35m'
NC='\033[0m'
log_info() { printf "${BLUE}[INFO]${NC} %s\n" "$1"; }
log_success() { printf "${GREEN}[OK]${NC} %s\n" "$1"; }
log_warning() { printf "${YELLOW}[WARN]${NC} %s\n" "$1"; }
log_error() { printf "${RED}[ERROR]${NC} %s\n" "$1"; }
log_highlight() { printf "${CYAN}[HIGHLIGHT]${NC} %s\n" "$1"; }
detect_memory() {
local mem_kb=$(grep MemTotal /proc/meminfo | awk '{print $2}')
printf '%s\n' "$((mem_kb / 1024))"
}
detect_cpu_cores() {
grep -c ^processor /proc/cpuinfo
}
get_current_connections() {
if [ -f /proc/sys/net/netfilter/nf_conntrack_count ]; then
cat /proc/sys/net/netfilter/nf_conntrack_count
else
printf '%s\n' "0"
fi
}
get_best_congestion_control() {
local available
available=$(cat /proc/sys/net/ipv4/tcp_available_congestion_control)
for algo in bbr cubic reno; do
if printf '%s\n' "$available" | grep -q "$algo"; then
printf '%s\n' "$algo"
return
fi
done
printf '%s\n' "$(printf '%s\n' "$available" | awk '{print $1}')"
}
# Get current value dynamically - this is the key fix
get_current_value() {
local setting="$1"
case "$setting" in
"rmem_max")
cat /proc/sys/net/core/rmem_max 2>/dev/null || printf "%s" "unknown"
;;
"wmem_max")
cat /proc/sys/net/core/wmem_max 2>/dev/null || printf "%s" "unknown"
;;
"tcp_rmem")
cat /proc/sys/net/ipv4/tcp_rmem 2>/dev/null | tr -s '\t' ' ' | sed 's/^[[:space:]]*//' | sed 's/[[:space:]]*$//' || printf "%s" "unknown"
;;
"tcp_wmem")
cat /proc/sys/net/ipv4/tcp_wmem 2>/dev/null | tr -s '\t' ' ' | sed 's/^[[:space:]]*//' | sed 's/[[:space:]]*$//' || printf "%s" "unknown"
;;
"tcp_congestion_control")
cat /proc/sys/net/ipv4/tcp_congestion_control 2>/dev/null || printf "%s" "unknown"
;;
"nf_conntrack_max")
cat /proc/sys/net/netfilter/nf_conntrack_max 2>/dev/null || printf "%s" "unknown"
;;
"netdev_max_backlog")
cat /proc/sys/net/core/netdev_max_backlog 2>/dev/null || printf "%s" "unknown"
;;
"somaxconn")
cat /proc/sys/net/core/somaxconn 2>/dev/null || printf "%s" "unknown"
;;
"active_connections")
get_current_connections
;;
*)
printf "%s" "unknown"
;;
esac
}
calculate_buffer_sizes() {
local mem_mb=$1
local cores=$2
if [ "$mem_mb" -ge 3072 ]; then
rmem_max=16777216; wmem_max=16777216
tcp_rmem="4096 262144 16777216"; tcp_wmem="4096 262144 16777216"
conntrack_max=262144; netdev_backlog=5000; somaxconn=16384
elif [ "$mem_mb" -ge 1536 ]; then
rmem_max=8388608; wmem_max=8388608
tcp_rmem="4096 131072 8388608"; tcp_wmem="4096 131072 8388608"
conntrack_max=131072; netdev_backlog=2500; somaxconn=8192
elif [ "$mem_mb" -ge 512 ]; then
rmem_max=4194304; wmem_max=4194304
tcp_rmem="4096 65536 4194304"; tcp_wmem="4096 65536 4194304"
conntrack_max=65536; netdev_backlog=1000; somaxconn=4096
else
rmem_max=1048576; wmem_max=1048576
tcp_rmem="4096 32768 1048576"; tcp_wmem="4096 32768 1048576"
conntrack_max=32768; netdev_backlog=500; somaxconn=2048
fi
if [ "$cores" -gt 4 ]; then
netdev_backlog=$((netdev_backlog * 2))
somaxconn=$((somaxconn * 2))
elif [ "$cores" -gt 2 ]; then
netdev_backlog=$((netdev_backlog + netdev_backlog / 2))
somaxconn=$((somaxconn + somaxconn / 2))
fi
}
format_bytes() {
local bytes=$1
if [ "$bytes" = "unknown" ]; then
printf '%s' "unknown"
return
fi
if [ "$bytes" -ge 1048576 ]; then
printf '%s' "$((bytes / 1048576))MB"
elif [ "$bytes" -ge 1024 ]; then
printf '%s' "$((bytes / 1024))KB"
else
printf '%s' "${bytes}B"
fi
}
values_equal() {
local current="$1"
local new="$2"
if [ "$current" = "unknown" ] || [ "$new" = "unknown" ]; then
return 1
fi
local norm_current=$(printf '%s\n' "$current" | tr -s ' \t' ' ' | sed 's/^[[:space:]]*//' | sed 's/[[:space:]]*$//')
local norm_new=$(printf '%s\n' "$new" | tr -s ' \t' ' ' | sed 's/^[[:space:]]*//' | sed 's/[[:space:]]*$//')
[ "$norm_current" = "$norm_new" ]
}
show_comparison() {
printf '\n'
printf "BEFORE vs AFTER COMPARISON\n"
printf '\n'
local max_setting=7
local max_value=6
local status_width=11
local single_settings="rmem_max wmem_max tcp_congestion_control nf_conntrack_max netdev_max_backlog somaxconn"
for setting in $single_settings; do
[ ${#setting} -gt $max_setting ] && max_setting=${#setting}
done
local tcp_items="tcp_rmem (min) tcp_rmem (default) tcp_rmem (max) tcp_wmem (min) tcp_wmem (default) tcp_wmem (max)"
for item in $tcp_items; do
[ ${#item} -gt $max_setting ] && max_setting=${#item}
done
for setting in $single_settings; do
local current_value=$(get_current_value "$setting")
local new_value
case "$setting" in
"rmem_max") new_value="$rmem_max" ;;
"wmem_max") new_value="$wmem_max" ;;
"tcp_congestion_control") new_value="$best_congestion" ;;
"nf_conntrack_max") new_value="$conntrack_max" ;;
"netdev_max_backlog") new_value="$netdev_backlog" ;;
"somaxconn") new_value="$somaxconn" ;;
esac
local display_current display_new
case "$setting" in
"rmem_max"|"wmem_max")
display_current="$(format_bytes "$current_value")"
display_new="$(format_bytes "$new_value")"
;;
*)
display_current="$current_value"
display_new="$new_value"
;;
esac
[ ${#display_current} -gt $max_value ] && max_value=${#display_current}
[ ${#display_new} -gt $max_value ] && max_value=${#display_new}
done
for proto in rmem tcp_wmem; do
local cur=$(get_current_value "${proto/tcp_/tcp_}")
local new=$(eval echo "\$tcp_${proto/tcp_}")
if [ "$cur" != "unknown" ]; then
for val in $(echo "$cur") $(echo "$new"); do
[ ${#val} -gt $max_value ] && max_value=${#val}
done
fi
done
max_setting=$((max_setting + 1))
max_value=$((max_value + 1))
local sep_setting sep_value sep_status
sep_setting=$(printf '%*s' "$max_setting" '' | tr ' ' '-')
sep_value=$(printf '%*s' "$max_value" '' | tr ' ' '-')
sep_status=$(printf '%*s' "$status_width" '' | tr ' ' '-')
printf "%-${max_setting}s| %-${max_value}s| %-${max_value}s| %-${status_width}s\n" "Setting" "Before" "After" "Status"
printf "%s+-%s+-%s+-%s\n" "$sep_setting" "$sep_value" "$sep_value" "$sep_status"
print_row() {
local setting="$1" current_val="$2" new_val="$3" status="$4"
printf "%-${max_setting}s| %-${max_value}s| %-${max_value}s| %s\n" "$setting" "$current_val" "$new_val" "$status"
}
for setting in $single_settings; do
local current_value=$(get_current_value "$setting")
local new_value status
case "$setting" in
"rmem_max") new_value="$rmem_max" ;;
"wmem_max") new_value="$wmem_max" ;;
"tcp_congestion_control") new_value="$best_congestion" ;;
"nf_conntrack_max") new_value="$conntrack_max" ;;
"netdev_max_backlog") new_value="$netdev_backlog" ;;
"somaxconn") new_value="$somaxconn" ;;
esac
local display_current display_new
case "$setting" in
"rmem_max"|"wmem_max")
display_current="$(format_bytes "$current_value")"
display_new="$(format_bytes "$new_value")"
;;
*)
display_current="$current_value"
display_new="$new_value"
;;
esac
if values_equal "$current_value" "$new_value"; then
status="Same"
else
status="Changed"
if [ "$current_value" != "unknown" ] && [ "$new_value" != "unknown" ]; then
case "$setting" in
"rmem_max"|"wmem_max"|"netdev_max_backlog"|"somaxconn"|"nf_conntrack_max")
if [ "$new_value" -gt "$current_value" ] 2>/dev/null; then
status="↑ Increased"
elif [ "$new_value" -lt "$current_value" ] 2>/dev/null; then
status="↓ Optimized"
fi
;;
esac
fi
fi
print_row "$setting" "$display_current" "$display_new" "$status"
done
print_tcp_rows() {
local name="$1" cur="$2" new="$3"
if [ "$cur" = "unknown" ]; then
print_row "${name} (min)" "unknown" "$(echo "$new" | awk '{print $1}')" "Unknown"
print_row "${name} (default)" "unknown" "$(echo "$new" | awk '{print $2}')" "Unknown"
print_row "${name} (max)" "unknown" "$(echo "$new" | awk '{print $3}')" "Unknown"
return
fi
local c1 c2 c3 n1 n2 n3 s1 s2 s3
c1=$(echo "$cur" | awk '{print $1}'); n1=$(echo "$new" | awk '{print $1}')
c2=$(echo "$cur" | awk '{print $2}'); n2=$(echo "$new" | awk '{print $2}')
c3=$(echo "$cur" | awk '{print $3}'); n3=$(echo "$new" | awk '{print $3}')
s1="Same"; s2="Same"; s3="Same"
[ "$c1" != "$n1" ] && s1="Changed"
[ "$c2" != "$n2" ] && s2="Changed"
[ "$c3" != "$n3" ] && s3="Changed"
[ "$n1" -gt "$c1" ] 2>/dev/null && s1="↑ Increased"
[ "$n1" -lt "$c1" ] 2>/dev/null && s1="↓ Decreased"
[ "$n2" -gt "$c2" ] 2>/dev/null && s2="↑ Increased"
[ "$n2" -lt "$c2" ] 2>/dev/null && s2="↓ Decreased"
[ "$n3" -gt "$c3" ] 2>/dev/null && s3="↑ Increased"
[ "$n3" -lt "$c3" ] 2>/dev/null && s3="↓ Decreased"
print_row "${name} (min)" "$c1" "$n1" "$s1"
print_row "${name} (default)" "$c2" "$n2" "$s2"
print_row "${name} (max)" "$c3" "$n3" "$s3"
}
print_tcp_rows "tcp_rmem" "$(get_current_value tcp_rmem)" "$tcp_rmem"
print_tcp_rows "tcp_wmem" "$(get_current_value tcp_wmem)" "$tcp_wmem"
printf "%s+-%s+-%s+-%s\n" "$sep_setting" "$sep_value" "$sep_value" "$sep_status"
print_row "active_connections" "$(get_current_connections)" "$(get_current_connections)" "Same"
printf '\n'
printf "Legend:\n"
printf " Same - No change needed\n"
printf " ↑ Increased - Value will be increased for better performance\n"
printf " ↓ Optimized - Value will be reduced for memory optimization\n"
printf " Changed - Value will be modified\n"
printf '\n'
}
verify_applied_settings() {
printf '\n'
log_info "=== Post-Application Verification ==="
local verification_failed=0
verify_setting() {
local setting_name="$1"
local expected_value="$2"
local actual_value="$3"
local display_name="$4"
if values_equal "$actual_value" "$expected_value"; then
log_success "$display_name: $(format_bytes "$actual_value" 2>/dev/null || printf "%s" "$actual_value")"
else
log_warning "$display_name: $actual_value (expected: $expected_value)"
verification_failed=1
fi
}
# Verify each setting using the same dynamic fetch method
verify_setting "rmem_max" "$rmem_max" "$(get_current_value "rmem_max")" "rmem_max"
verify_setting "wmem_max" "$wmem_max" "$(get_current_value "wmem_max")" "wmem_max"
verify_setting "netdev_max_backlog" "$netdev_backlog" "$(get_current_value "netdev_max_backlog")" "netdev_max_backlog"
verify_setting "somaxconn" "$somaxconn" "$(get_current_value "somaxconn")" "somaxconn"
verify_setting "tcp_rmem" "$tcp_rmem" "$(get_current_value "tcp_rmem")" "tcp_rmem"
verify_setting "tcp_wmem" "$tcp_wmem" "$(get_current_value "tcp_wmem")" "tcp_wmem"
# Overall result
if [ "$verification_failed" -eq 0 ]; then
log_success "All settings verified successfully!"
else
log_warning "Some settings may not have been applied correctly"
printf '\n'
log_info "This may be due to:"
printf " - Kernel module not loaded (e.g., nf_conntrack)\n"
printf " - Insufficient permissions\n"
printf " - Kernel version compatibility\n"
printf " - Hardware limitations\n"
printf '\n'
log_info "Running 'dmesg | tail' might provide more information"
fi
}
show_performance_impact() {
printf "Performance Impact Summary\n"
printf '\n'
mem_mb=$(detect_memory)
cores=$(detect_cpu_cores)
printf "System Profile: %dMB RAM, %d CPU cores\n" "$mem_mb" "$cores"
printf '\n'
changes_found=0
improvements=""
# Check for actual improvements by comparing current vs new values
current_rmem=$(get_current_value rmem_max)
current_wmem=$(get_current_value wmem_max)
current_backlog=$(get_current_value netdev_max_backlog)
current_somaxconn=$(get_current_value somaxconn)
if ! values_equal "$current_rmem" "$rmem_max" && [ "$current_rmem" != unknown ] && [ "$current_rmem" -gt 0 ] 2>/dev/null; then
rmem_impr=$(( (rmem_max - current_rmem) * 100 / current_rmem ))
if [ "$rmem_impr" -gt 0 ]; then
improvements="${improvements}Receive buffer: +${rmem_impr}% increase -> Better download performance\n"
changes_found=1
elif [ "$rmem_impr" -lt 0 ]; then
improvements="${improvements}Receive buffer: ${rmem_impr}% decrease -> Memory optimized\n"
changes_found=1
fi
fi
if ! values_equal "$current_wmem" "$wmem_max" && [ "$current_wmem" != unknown ] && [ "$current_wmem" -gt 0 ] 2>/dev/null; then
wmem_impr=$(( (wmem_max - current_wmem) * 100 / current_wmem ))
if [ "$wmem_impr" -gt 0 ]; then
improvements="${improvements}Send buffer: +${wmem_impr}% increase -> Better upload performance\n"
changes_found=1
elif [ "$wmem_impr" -lt 0 ]; then
improvements="${improvements}Send buffer: ${wmem_impr}% decrease -> Memory optimized\n"
changes_found=1
fi
fi
if ! values_equal "$current_backlog" "$netdev_backlog" && [ "$current_backlog" != unknown ] && [ "$current_backlog" -gt 0 ] 2>/dev/null; then
backlog_impr=$(( (netdev_backlog - current_backlog) * 100 / current_backlog ))
if [ "$backlog_impr" -gt 0 ]; then
improvements="${improvements}Network backlog: +${backlog_impr}% increase -> Better packet processing\n"
changes_found=1
fi
fi
if ! values_equal "$current_somaxconn" "$somaxconn" && [ "$current_somaxconn" != unknown ] && [ "$current_somaxconn" -gt 0 ] 2>/dev/null; then
connq_impr=$(( (somaxconn - current_somaxconn) * 100 / current_somaxconn ))
if [ "$connq_impr" -gt 0 ]; then
improvements="${improvements}Connection queue: +${connq_impr}% increase -> More concurrent connections\n"
changes_found=1
fi
fi
if [ "$changes_found" -eq 1 ]; then
printf "Performance Improvements:\n"
printf "%b" "$improvements"
else
printf "System is already optimally configured for your hardware\n"
printf "No significant changes needed\n"
fi
printf '\n'
printf "Expected Benefits:\n"
printf " - Reduced packet drops under high load\n"
printf " - Better throughput for large file transfers\n"
printf " - Improved responsiveness for multiple connections\n"
printf " - Optimized memory usage for your hardware\n"
printf '\n'
}
remove_optimizer() {
printf "Network Optimizer Removal Tool\n"
printf "==============================\n"
if [ ! -f "$CONFIG_FILE" ]; then
log_info "No optimization config found"
return 0
fi
printf "Do you want to remove the existing optimization config? (y/N): "
read -r confirm_remove
if [ "$confirm_remove" != "y" ] && [ "$confirm_remove" != "Y" ]; then
log_info "Removal cancelled by user"
return 0
fi
local backup_file=""
for backup in "${CONFIG_FILE}.backup."*; do
[ -f "$backup" ] && { backup_file="$backup"; break; }
done
if [ -n "$backup_file" ]; then
log_info "Restoring from backup: $backup_file"
cp "$backup_file" "$CONFIG_FILE"
sysctl -p "$CONFIG_FILE" >/dev/null 2>&1
log_success "Original settings restored"
else
log_info "No backup found – removing config file"
rm "$CONFIG_FILE"
log_success "Config file removed"
log_highlight "Reboot required to return to system defaults"
fi
}
optimizer_main() {
printf "Dynamic Network Performance Optimizer\n"
printf "=====================================\n"
if [ -f "$CONFIG_FILE" ]; then
log_warning "Existing config detected: $CONFIG_FILE"
remove_optimizer
exit 0
fi
printf '\n'
log_info "=== System Analysis ==="
local mem_mb=$(detect_memory)
local cores=$(detect_cpu_cores)
local best_congestion=$(get_best_congestion_control)
log_info "Detected RAM: ${mem_mb}MB"
log_info "Detected CPU cores: $cores"
log_info "Best congestion control: $best_congestion"
calculate_buffer_sizes "$mem_mb" "$cores"
show_comparison
show_performance_impact
printf "Do you want to apply these changes? (y/N): "
read -r confirm
if [ "$confirm" != "y" ] && [ "$confirm" != "Y" ]; then
log_info "Operation cancelled by user"
exit 0
fi
if [ -f "$CONFIG_FILE" ]; then
local backup_file="${CONFIG_FILE}.backup.$(date +%Y%m%d_%H%M%S)"
cp "$CONFIG_FILE" "$backup_file"
log_info "Backed up existing config to: $backup_file"
fi
log_info "Creating configuration: $CONFIG_FILE"
cat > "$CONFIG_FILE" << CONFIG_EOF
net.core.rmem_max = $rmem_max
net.core.wmem_max = $wmem_max
net.ipv4.tcp_rmem = $tcp_rmem
net.ipv4.tcp_wmem = $tcp_wmem
net.ipv4.tcp_congestion_control = $best_congestion
net.ipv4.tcp_fastopen = 3
net.ipv4.tcp_keepalive_probes = 3
net.netfilter.nf_conntrack_max = $conntrack_max
net.core.netdev_max_backlog = $netdev_backlog
net.core.somaxconn = $somaxconn
CONFIG_EOF
printf '\n'
log_info "Applying configuration"
if sysctl -p "$CONFIG_FILE" >/dev/null 2>&1; then
log_success "Configuration applied successfully"
else
log_warning "Some settings may have failed (check kernel support)"
fi
verify_applied_settings
printf '\n'
log_success "Network optimization completed!"
log_highlight "Reboot recommended for full effect and persistent changes"
printf '\n'
log_info "Current memory usage:"
free -h
}
if [ "$0" = "${0#*/}" ] || [ "${0##*/}" = "$(basename "$0")" ]; then
optimizer_main "$@"
fi
SCRIPT_END
chmod +x "$TMP/dynamic-network-optimizer.sh"
sh "$TMP/dynamic-network-optimizer.sh"