Nodeos

nodeos is the core service daemon that runs on every EOSIO node. It can be configured to process smart contracts, validate transactions, produce blocks containing valid transactions, and confirm blocks to record them on the blockchain.

Depending on the type of system (whether it is baremetal or cloud) you have configured to run your state history, you might want to isolate the cores to prevent the operating system from utilizing them for certain system processes.

Linux provides the capability to allocate certain process ID's (identifier used to uniquely identify a process) to specific CPU cores. The benefit here is the ability to seperate CPU bound applications and have a specific affinity set to get most out of the core frequencies.

Scenarios

• You have to run one of Atomic, History or Hyperion API with a SHIP instance (which is risky, but in terms of budgeting preferences), but would like the chain data to be syncronized in a performent manner, while the API requires as much cores as it is entitled too.

To enable process/core isolation, you need to add the following configuration to your Kernel Loader

NOTE: In the example, the intention was to isolate cores 7,9,11. Total amount of CPU's = 12

NOTE: cpu id's start at 0

GRUB_CMDLINE_LINUX_DEFAULT="isolcpus=8,10,12"

Update your grub configuration and reboot your system once

update-grub && reboot

If you would like to test your recent changes, you can install a stress utility and launch a stress test against all of the cores to ensure the isolated cores are not used since they should be unavailable unless processes has been delegated to those

apt install -y stress

To perform the test against all cpu's

stress -c 12

To schedule a process on a particular core

taskset -cp <isolated core id> <process id/id's>

Another way to optimize the nodeos processes would be to set the scheduling parameters to type (SCHED_BATCH) which is designed for non-interactive, CPU-bound applications. It uses longer timeslices (short time frame that gets assigned to process for CPU execution). These processes are normally scheduled with lower priority, but may result in considerable speed improvements.

To schedule a process with SCHED_BATCH parameter

schedtool -B <process id/id's>

nodeos startup script

By this time you should be aware that nodes should execute as a daemon process to prevent the need of an interactive session during the lifetime of the process. If your session ends without gracefull termination, your state history will be out-of-sync, and you will need to replay several sets of data which is time consuming, as well put the dependent systems at risk as they should be level with the headblock

When launching nodeos, there will be 3 process id's which will be registered. Ideally, you would like all 3 process id's allocated to seperate cores which is isolated from system processes (benefits explained above) You can add the following to your startup script to allocate the nodeos pids automatically.

NOTE: (This is still based of the example of having isolated cores 7,9,11). This will schedule the nodes pids each on a seperate isolated CPU and schedule it as a SCHED_BATCH service

PIDS=`pidof nodeos`
arr=($PIDS)
NODEPROC1=${arr[0]}
NODEPROC2=${arr[1]}
NODEPROC3=${arr[2]}
echo $NODEPROC1
echo $NODEPROC2
echo $NODEPROC3
taskset -cp 7 $NODEPROC1 && schedtool -B $NODEPROC1
taskset -cp 9 $NODEPROC2 && schedtool -B $NODEPROC2
taskset -cp 11 $NODEPROC3 && schedtool -B $NODEPROC3