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Maniphest T7423

Add kernel options isolcpus, nohz_full, rcu_nocbs, hugepages, numa_balancing
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Description

Summary

Add kernel options isolcpus, nohz_full, rcu_nocbs, default_hugepagesz, hugepages, hugepagesz, numa_balancing

The isolcpus kernel parameter can be used to specify CPUs to be isolated from the general SMP balancing and scheduler algorithms. The argument is a CPU list:

isolcpus=<cpu number>,….,<cpu number>

Use case

Use some cores exclusively for VPP.

Additional information

Proposed CLI

set system option kernel isolcpus '4,5,6,7'

Example of usecase:

set system option kernel isolcpus '4,5,6,7'

set vpp settings cpu main-core '4'
set vpp settings cpu corelist-workers '5-7'
set vpp settings interface eth2 dpdk-options promisc
set vpp settings interface eth2 driver 'dpdk'

Check:

%Cpu0  :  0.0 us,  0.3 sy,  0.0 ni, 99.7 id,  0.0 wa,  0.0 hi,  0.0 si,  0.0 st 
%Cpu1  :  0.0 us,  0.3 sy,  0.0 ni, 99.7 id,  0.0 wa,  0.0 hi,  0.0 si,  0.0 st 
%Cpu2  :  0.0 us,  0.0 sy,  0.0 ni,100.0 id,  0.0 wa,  0.0 hi,  0.0 si,  0.0 st 
%Cpu3  :  0.3 us,  0.3 sy,  0.0 ni, 99.3 id,  0.0 wa,  0.0 hi,  0.0 si,  0.0 st 
%Cpu4  :  1.3 us,  1.7 sy,  0.0 ni, 96.7 id,  0.0 wa,  0.0 hi,  0.0 si,  0.3 st 
%Cpu5  : 99.3 us,  0.3 sy,  0.0 ni,  0.0 id,  0.0 wa,  0.0 hi,  0.0 si,  0.3 st 
%Cpu6  : 99.3 us,  0.7 sy,  0.0 ni,  0.0 id,  0.0 wa,  0.0 hi,  0.0 si,  0.0 st 
%Cpu7  : 99.3 us,  0.3 sy,  0.0 ni,  0.0 id,  0.0 wa,  0.0 hi,  0.0 si,  0.3 st 
MiB Mem :  16009.8 total,  12974.3 free,   2784.1 used,    519.3 buff/cache     
MiB Swap:      0.0 total,      0.0 free,      0.0 used.  13225.7 avail Mem

Details

Version
-
Is it a breaking change?
Perfectly compatible
Issue type
Feature (new functionality)

Related Objects

Event Timeline

Viacheslav created this task.May 1 2025, 8:15 AM
Viacheslav triaged this task as Normal priority.
Viacheslav updated the task description. (Show Details)May 1 2025, 8:50 AM
Viacheslav renamed this task from Add kernel option isolcpus to Add kernel options isolcpus, nohz_full, rcu_nocbs, hugepages, numa_balancing.May 1 2025, 9:36 AM
Viacheslav updated the task description. (Show Details)
pasik subscribed.May 1 2025, 1:43 PM
Viacheslav changed the task status from Open to In progress.May 2 2025, 3:13 PM
Viacheslav claimed this task.

PR https://github.com/vyos/vyos-1x/pull/4491

set system option kernel cpu disable-nmi-watchdog
set system option kernel cpu isolate-cpus '1,2,4-5'
set system option kernel cpu nohz-full '1,2,4-5'
set system option kernel cpu rcu-no-cbs '1,2,4-5'
set system option kernel disable-hpet
set system option kernel disable-mce
set system option kernel disable-softlockup
set system option kernel memory default-hugepage-size '2M'
set system option kernel memory disable-numa-balancing
set system option kernel memory hugepage-count '256'
set system option kernel memory hugepage-size '2M'
Viacheslav mentioned this in rVYOSONEXc823a6908468: T7423: Add kernel boot options isolcpus, hugepages, numa_balancing.May 9 2025, 7:13 PM
Restricted Repository Identity mentioned this in rVYOSONEX4ed8419dc12e: Merge pull request #4491 from sever-sever/T7423.May 9 2025, 7:13 PM
dmbaturin closed this task as Resolved.May 28 2025, 10:03 PM
dmbaturin added a project: VyOS 1.5 Circinus (1.5-stream-2025-Q2).
dmbaturin changed Is it a breaking change? from Unspecified (possibly destroys the router) to Perfectly compatible.
dmbaturin moved this task from Open to Finished on the VyOS 1.5 Circinus (1.5-stream-2025-Q2) board.
dmbaturin moved this task from Need Triage to Completed on the VyOS Rolling board.