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VPP Memory Configuration
VPP heavily relies on hugepages for its memory management. Hugepages are larger memory pages that reduce the overhead of page management and improve performance for applications that require large amounts of memory, such as VPP.
VPP supports both 2MB and 1GB hugepages, but the default and most commonly used size is 2MB. The choice of hugepage size can impact performance, with larger pages generally providing better performance for memory-intensive applications.
Before configuring memory in VPP dataplane settings, you need to ensure that hugepages are enabled and properly configured on your system.
To configure memory settings for VPP, you can use the following commands in the VPP CLI:
VPP uses a main heap as a central memory pool for FIB data structures entry allocations.
Efficient memory management is crucial for VPP’s performance, and the main heap plays a significant role in this.
It can be configured using the following command:
Sets the main heap page size for VPP.
Sets the main heap size for VPP.
Physical Memory Configuration
VPP uses physical memory for packet buffers and interface operations.
The physmem setting controls how much memory VPP can allocate for
these operations.
Sets the maximum amount of physical memory VPP can use for packet processing and interface buffers.
Default: 16GB (usually sufficient for most deployments)
You may need to modify the value for high-throughput environments with many interfaces, large packet buffers, very high packet rates, or memory-constrained systems where you need to limit VPP’s memory usage.
Physmem independent of main heap size — physmem is for packet buffers, main heap is for routing tables.
See also
VPP Buffer Configuration - for controlling buffer allocation within physmem
Common configurations
# Reduce for memory-constrained systems
set vpp settings physmem max-size 4G
# Increase for high-throughput environments
set vpp settings physmem max-size 32G
Stats Memory Configuration
VPP uses a dedicated statistics memory segment to store runtime counters and telemetry data. This segment is used by the VPP CLI and monitoring tools to access performance and status information.
The statistics segment is allocated from hugepage memory and can be configured independently from the main heap and physmem settings.
You can configure statistics memory using the following commands:
Sets the hugepage page size used for the statistics memory segment.
Sets the total size of the statistics memory segment.
Increasing this value may be required in large deployments with many interfaces or enabled features that generate a high number of counters.
Statistics memory is used only for telemetry and monitoring. It does not affect packet buffer allocation or routing table memory.
Troubleshooting
Improper configuration of main heap size can lead to performance degradation or even system instability. If VPP runs out of memory in the main heap, it may crash or exhibit erratic behavior. Symptoms you may observe include:
Increased latency or packet loss
Crashes or restarts of VPP processes, especially during routing table population (for example, BGP session establishment)
Error messages related to memory allocation failures
You need to tune the main heap size based on expected FIB entries. Pay attention: the same amount of routes with a single next-hop and with multiple next-hops will consume different amounts of memory.
For physmem, insufficient allocation can lead to packet drops, interface initialization failures, and overall degraded performance. Symptoms include:
Packet drops or failures to allocate buffers
Increased latency or jitter in packet processing
Crashes or restarts of VPP processes under heavy load
You need to tune the physmem settings based on expected traffic patterns and interface usage. Monitor memory usage closely and adjust the configuration as needed to ensure optimal performance.