Ultra Low Latency Server Huge-page Config
#
# Uncomment the following to stop low-level messages on console
kernel.printk = 3 4 1 3
# /etc/sysctl.conf - Configuration file for setting system variables
# See /etc/sysctl.d/ for additional system variables.
# See sysctl.conf (5) for information.
#
net.ipv4.tcp_fin_timeout = 1
#
# Increase maximum amount of memory allocated to shm
# Increase size of file handles and inode cache
fs.file-max = 209715200000
#
# Increase size of Kernel Memory Sharing
kernel.shmmax = 51539607552
kernel.shmmni = 515396075
kernel.shmall = 51539607552
vm.hugepages_treat_as_movable=24576
vm.nr_hugepages=24576
vm.nr_hugepages_mempolicy=24576
vm.nr_overcommit_hugepages=24576
vm.hugetlb_shm_group=0
#
# This will increase the amount of memory available for socket input/output queues
# Increase number of incoming connections
net.core.somaxconn = 65535
net.ipv4.tcp_rmem = 4096 51539607552 51539607552
# Maximum Socket Receive Buffer
net.core.rmem_max = 51539607552
# Default Socket Receive Buffer
net.core.rmem_default = 51539607552
net.ipv4.tcp_wmem = 4096 65536 51539607552
# Maximum Socket Send Buffer
net.core.wmem_max = 51539607552
# Default Socket Send Buffer
net.core.wmem_default = 31457280
net.core.optmem_max = 51539607552
net.ipv4.tcp_max_orphans = 51539607552
net.ipv4.tcp_max_syn_backlog = 51539607552
# Number of times SYNACKs for passive TCP connection.
net.ipv4.tcp_synack_retries = 2
net.ipv4.tcp_syn_retries = 2
# Increase the maximum amount of option memory buffers
net.core.optmem_max = 51539607552
##############################################################3
# Do less swapping
vm.swappiness = 0
vm.dirty_ratio = 1
vm.dirty_background_ratio = 1
### GENERAL NETWORK SECURITY OPTIONS ###
# Allowed local port range
net.ipv4.ip_local_port_range = 1 65535
# Protect Against TCP Time-Wait
net.ipv4.tcp_rfc1337 = 1
##############################################################3
### TUNING NETWORK PERFORMANCE ###
##############################################################3
# Functions previously found in netbase
#
# Uncomment the next two lines to enable Spoof protection (reverse-path filter)
# Turn on Source Address Verification in all interfaces to
# prevent some spoofing attacks
net.ipv4.conf.default.rp_filter=1
net.ipv4.conf.all.rp_filter=1
# Uncomment the next line to enable TCP/IP SYN cookies
# See http://lwn.net/Articles/277146/
# Note: This may impact IPv6 TCP sessions too
net.ipv4.tcp_syncookies=1
# Uncomment the next line to enable packet forwarding for IPv4
net.ipv4.ip_forward=1
# Uncomment the next line to enable packet forwarding for IPV4/IPv6
# Enabling this option disables Stateless Address Autoconfiguration
# based on Router Advertisements for this host
net.ipv6.conf.all.forwarding=1
net.ipv6.conf.all.forwarding=1
###################################################################
# Additional settings - these settings can improve the network
# security of the host and prevent against some network attacks
# including spoofing attacks and man in the middle attacks through
# redirection. Some network environments, however, require that these
# settings are disabled so review and enable them as needed.
#
# Do not accept ICMP redirects (prevent MITM attacks)
net.ipv4.conf.all.accept_redirects = 0
net.ipv6.conf.all.accept_redirects = 0
# _or_
# Accept ICMP redirects only for gateways listed in our default
# gateway list (enabled by default)
# net.ipv4.conf.all.secure_redirects = 1
#
# Do not send ICMP redirects (we are not a router)
net.ipv4.conf.all.send_redirects = 0
#
# Do not accept IP source route packets (we are not a router)
net.ipv4.conf.all.accept_source_route = 0
net.ipv6.conf.all.accept_source_route = 0
#
# Log Martian Packets
net.ipv4.conf.all.log_martians = 1
#
###################################################################
# Magic system request Key
# 0=disable, 1=enable all
# Debian kernels have this set to 0 (disable the key)
# See https://www.kernel.org/doc/Documentation/sysrq.txt
# for what other values do
kernel.sysrq=0
###################################################################
# Protected links
#
# Protects against creating or following links under certain conditions
# Debian kernels have both set to 1 (restricted)
# See https://www.kernel.org/doc/Documentation/sysctl/fs.txt
fs.protected_hardlinks=0
fs.protected_symlinks=0
#
###################################################################
Optimizing and Tuning R815-Server via Ultra/Low-Latency Configurations:
0. tuned-adm profile latency-performance
0.1 for MF in `find /proc/irq -name *smp_affinity` ; do awk -F, \ '{for(i=1;i<NF;i++)printf("00000000,");printf("%8.8x\n",and(0x00000001, strtonum("0x"$NF)))}' \ $MF > $MF ; done
1. find /sys/kernel/slab -name 'cpu_partial' -exec sh -c 'echo 0 > {}' \;
2. cset shield --cpu 1-63 --kthread=on
3.0 cset proc --move --pid=$$ --threads --toset=root
3.1 cset proc --move --pid=$$ --threads --toset=user
. grub2-mkconfig -o /boot/grub2/grub.cfg
or
.grub-mkconfig -o /boot/grub/grub.cfg
dnf install -y libhugetlbfs-utils
This is the 'Magic file'
/etc/sysctl.conf
The goal is to make the output of this program "happy"
sudo hugeadm --set-recommended-shmmax
This sets changes in motion immediately, though a reboot is suggested once everything is configured.
sysctl -p
We will make changes by echoing options to sysctl.conf
echo "vm.hugetlb_shm_group = 0" >> /etc/sysctl.conf
echo "vm.min_free_kbytes = 112640" >> /etc/sysctl.conf
echo "vm.nr_hugepages = 8600" >> /etc/sysctl.conf
echo "kernel.shmmax = 18035507200" >> /etc/sysctl.conf
echo "vm.swappiness = 0" >> /etc/sysctl.conf
