tux-performance-tuning

NOTE: don't do any of this unless you understand all it's implications

https://engineering.linkedin.com/performance/optimizing-linux-memory-management-low-latency-high-throughput-databases

Linux's NUMA optimizations can be effectively disabled by doing the following:
  Turn zone reclaim mode off: add vm.zone_reclaim_mode = 0 to /etc/sysctl.conf and run sysctl -p to load the new settings.
  Enable NUMA interleaving for your application: run with numactl --interleave=all COMMAND 
These are now the defaults on all our production systems.

Filesystem benchmarking:
  fio --name TEST --eta-newline=5s --filename=fio-tempfile.dat --rw=randread --size=2g --io_size=4g --blocksize=4k --ioengine=libaio --fsync=1 --iodepth=1 --numjobs=1 --runtime=10 --group_reporting
  fio --name TEST --eta-newline=5s --filename=fio-tempfile.dat --rw=randrw --size=2g --io_size=4g --blocksize=4k --ioengine=libaio --fsync=1 --iodepth=1 --numjobs=1 --runtime=10 --group_reporting
  ioping -c 1000 -s 4k -S 1G -i 0 -G . >test1.txt

Minimize swapping
  echo "vm.swappiness=1" | sudo tee -a /etc/sysctl.d/42-swappiness.conf
  sysctl --system

disable spectre/meltdown mitigations
  kernel >= 5.2:      mitigations=off
  intel igpu:    i915.mitigations=off

disable apparmor
  apparmor=0

bfq io scheduler (>4.15 kernel)
  kernel commandline:
    scsi_mod.use_blk_mq=1
  /etc/modules-load.d/bfq.conf:
    bfq
  /etc/udev/rules.d/50-scheduler.rules:
    ACTION=="add|change", KERNEL=="sd[a-z]", ATTR{queue/scheduler}="bfq"  [https://gist.github.com/wooptoo/835f377d88ef9fb11a21e735630d7470]
  sudo udevadm control --reload
  sudo udevadm trigger

check trim support:
sudo hdparm -I /dev/[...] | grep TRIM

Update grub
  update-grub

Disable journaling (don't do this):
  boot into single user mode
  remount / as ro
  sudo tune2fs -O ^has_journal $SSD_DRIVE

Avoid slow shutdown due to CUPS
  sudo EDITOR=vim systemctl edit cups-browsed
    [Service]
    TimeoutStopSec=1
  Alternatively:
    sudo systemctl stop cups-browsed.service
    sudo systemctl disable cups-browsed.service