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Diffstat (limited to 'docs/vpp/configuration/dataplane/cpu.md')
| -rw-r--r-- | docs/vpp/configuration/dataplane/cpu.md | 21 |
1 files changed, 21 insertions, 0 deletions
diff --git a/docs/vpp/configuration/dataplane/cpu.md b/docs/vpp/configuration/dataplane/cpu.md index d92f6587..bd67b91e 100644 --- a/docs/vpp/configuration/dataplane/cpu.md +++ b/docs/vpp/configuration/dataplane/cpu.md @@ -35,6 +35,27 @@ This parameter defines the total number of CPU cores allocated to VPP. ```{cfgcmd} set vpp settings resource-allocation cpu-cores \<core-number\> ``` +:::{important} +`cpu-cores` requires at least the same number of CPUs to be isolated from the +kernel scheduler with `set system option kernel cpu isolate-cpus`. VPP takes +its main core and its worker cores from the isolated set, and the commit is +rejected when fewer CPUs are isolated than requested: + +```none +Not enough isolated CPU cores available: 2 requested, but only 0 isolated. +To isolate CPUs please use command +"set system option kernel cpu isolate-cpus ..." save and reboot! +``` + +This applies even when `cpu-cores` is left at its default of `1`. VPP always +takes its main core from the isolated set, so at least one CPU has to be +isolated before the dataplane can be enabled at all. + +CPU isolation is a kernel option, so it has to be committed, saved and applied +with a reboot **before** VPP is configured — the two cannot be set in the same +commit. See {ref}`Optimal Configuration Example <vpp-config-setup-order>`. +::: + The system automatically assigns cores using the following rules: > - The first two CPU cores are always reserved for the operating system and |