[Sony Xperia P, U, Sola, Go] krabappel2548:
Here are some more tweaks ;) Feel free to add them to the first post ;)

To make them work:

1. make a new file in /system/etc/init.d, name it sysctl_tweaks

2. make a new file in /system/etc, name it sysctl.conf

3. Paste the right code in the right file ;)

1. sysctl_tweaks

#!/system/bin/sh
# grep sysctl /etc/init.d/*
/etc/init.d/02vm:# Load /sys/etc/sysctl.conf
/etc/init.d/02vm:sysctl -p

2. sysctl.conf

#sysctl.conf file

############################
# Battery life tweaks #
############################
sysctl -w vm.dirty_writeback_centisecs=3000;
sysctl -w vm.dirty_expire_centisecs=500;

############################
# kernel tweaks #
############################

sysctl -w kernel.sched_features=15834233;
sysctl -w kernel.msgmni=1024;
sysctl -w kernel.msgmax=64000;
sysctl -w kernel.shmmax=268435456;
sysctl -w kernel.shmall=2097152;
sysctl -w kernel.sem="500 512000 100 2048";
sysctl -w kernel.hung_task_timeout_secs=0;
sysctl -w kernel.sched_latency_ns=18000000;
sysctl -w kernel.sched_compat_yield=1;
sysctl -w kernel.sched_shares_ratelimit=256000;
sysctl -w kernel.sched_child_runs_first=0;
sysctl -w kernel.threads-max=10000;
sysctl -w kernel.panic=30;
sysctl -w kernel.panic_on_oops=1;
sysctl -w kernel.sched_features=24189;
sysctl -w kernel.sched_min_granularity_ns=1500000;
sysctl -w kernel.sched_wakeup_granularity_ns=3000000;

############################
# CPU tweaks #
############################

# Queue size modifications
sysctl -w net.core.optmem_max=20480;
sysctl -w net.unix.max_dgram_qlen=50;

# Net Core Settings
# Location: /proc/sys/net/core
sysctl -w net.core.wmem_max=524288;
sysctl -w net.core.rmem_max=524288;
sysctl -w net.core.rmem_default=256960;
sysctl -w net.core.wmem_default=256960;

############################
# VM & Filesystem tweaks #
############################
sysctl -w fs.lease-break-time=10;
sysctl -w fs.file-max=65536;
sysctl -w vm.overcommit_memory=1;
sysctl -w vm.min_free_order_shift=4;
sysctl -w vm.block_dump=0;
sysctl -w vm.oom_dump_tasks=1;
sysctl -w vm.page-cluster=3;

############################
# Net Speed tweaks #
############################

# UnderUtilized Networking Tweaks below as recommended by avgjoemomma (from XDA)
sysctl -w net.ipv4.tcp_congestion_control=cubic;

# Hardening the TCP/IP stack to SYN attacks
sysctl -w net.ipv4.tcp_syncookies=1;
sysctl -w net.ipv4.conf.all.rp_filter=1;
sysctl -w net.ipv4.conf.default.rp_filter=1;
sysctl -w net.ipv4.tcp_synack_retries=2;
sysctl -w net.ipv4.tcp_syn_retries=2;
sysctl -w net.ipv4.tcp_max_syn_backlog=1024;
sysctl -w net.ipv4.tcp_max_tw_buckets=16384;
sysctl -w net.ipv4.icmp_echo_ignore_all=1;
sysctl -w net.ipv4.icmp_ignore_bogus_error_responses=1;
sysctl -w net.ipv4.tcp_no_metrics_save=1;
sysctl -w net.ipv4.tcp_fin_timeout=15;
sysctl -w net.ipv4.tcp_keepalive_time=1800;
sysctl -w net.ipv4.ip_forward=0;
sysctl -w net.ipv4.tcp_moderate_rcvbuf=1;
sysctl -w net.ipv4.route.flush=1;
sysctl -w net.ipv4.udp_rmem_min=6144;
sysctl -w net.ipv4.udp_wmem_min=6144;
sysctl -w net.ipv4.tcp_rfc1337=1;
sysctl -w net.ipv4.ip_no_pmtu_disc=0;
sysctl -w net.ipv4.tcp_ecn=0;
sysctl -w net.ipv4.tcp_sack=1;
sysctl -w net.ipv4.tcp_fack=1;

# Don't accept source routing
sysctl -w net.ipv4.conf.default.accept_source_route=0 ;
sysctl -w net.ipv4.conf.all.accept_source_route=0;

# Don't accept redirects
sysctl -w net.ipv4.conf.all.accept_redirects=0;
sysctl -w net.ipv4.conf.default.accept_redirects=0;
sysctl -w net.ipv4.conf.all.secure_redirects=0;
sysctl -w net.ipv4.conf.default.secure_redirects=0;

This is another init.d tweak ;) It's a battery calibration script

3. This is my battery calibration tweak

#!/system/bin/sh
# ========================================
# init.d script for KA Xperia SSpeed
# made by krabappel2548
# ========================================

SLEEP=120

if [ -e /data/.battery-calibrated ] ; then
exit 0
fi

(
while : ; do
LEVEL=$(cat /sys/class/power_supply/battery/capacity)
CUR=$(cat /sys/class/power_supply/battery/batt_current)
if [ "$LEVEL" == "100" ] && [ "$CUR" == "0" ] ; then
log -p i -t battery-calibration "*** LEVEL: $LEVEL CUR: $CUR***: calibrating..."
rm -f /data/system/batterystats.bin
touch /data/.battery-calibrated
exit 0
fi
# log -p i -t battery-calibration "*** LEVEL: $LEVEL CUR: $CUR ***: sleeping for $SLEEP s..."
sleep $SLEEP
done
) &

#Disable normalize sleeper
mount -t debugfs none /sys/kernel/debug
echo NO_NORMALIZED_SLEEPER > /sys/kernel/debug/sched_features

#battery tweaks (sleepers)
mount -t debugfs none /sys/kernel/debug
echo NO_NEW_FAIR_SLEEPERS > /sys/kernel/debug/sched_features;
echo NO_NORMALIZED_SLEEPERS > /sys/kernel/debug/sched_features;
umount /sys/kernel/debug