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authorYuriy Andamasov <yuriy@vyos.io>2026-05-06 23:24:45 +0300
committerYuriy Andamasov <yuriy@vyos.io>2026-05-06 23:24:45 +0300
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+---
+lastproofread: '2026-02-23'
+---
+
+(vpp-config-dataplane-cpu)=
+
+```{include} /_include/need_improvement.txt
+```
+
+
+# VPP Dataplane CPU Configuration
+
+VPP can utilize multiple CPU cores for better packet processing
+performance. Proper CPU configuration is essential for optimal
+throughput and low latency.
+
+VPP CPU assignment is handled automatically. You specify how many CPU
+cores VPP may use, and the system distributes them between the main
+thread and worker threads.
+
+:::{important}
+Review the system configuration settings page before changing CPU
+settings: {doc}`system`.
+:::
+
+If you don't configure CPU settings, VPP uses a single core for the
+main thread and doesn't create worker threads.
+
+## CPU Configuration Parameters
+
+### `cpu-cores`
+
+This parameter defines the total number of CPU cores allocated to VPP.
+
+```{cfgcmd} set vpp settings resource-allocation cpu-cores \<core-number\>
+```
+
+The system automatically assigns cores using the following rules:
+
+> - The first two CPU cores are always reserved for the operating system and
+> other services.
+> - The main VPP thread is assigned to the first available core after the
+> reserved ones.
+> - The remaining allocated cores are used for worker threads.
+
+For example:
+
+> - If cpu-cores is set to 1, VPP runs only a main thread.
+>
+> - If cpu-cores is set to 4, VPP uses:
+>
+> > - 1 core for the main thread
+> > - 3 cores for worker threads
+
+Choose a value based on available hardware resources and expected
+traffic load. Too few cores may limit performance, while too many can
+negatively impact other system services.
+
+## Potential Issues and Troubleshooting
+
+Improper CPU configuration can lead to issues such as:
+
+- VPP underperformance when not enough cores are assigned, or kernel
+ underperformance when too many cores are assigned to VPP.
+- Resource conflicts with other processes and services.
+
+Indicators of such issues are:
+
+- VPP or kernel forwarding performance is lower than expected
+- Degraded performance of system components or services, such as DNS,
+ DHCP, and dynamic routing