VPP Startup Settings

VPP Startup Settings #

CSIT code manipulates a number of VPP settings in startup.conf for optimized performance. List of common settings applied to all tests and test dependent settings follows.

Common Settings #

List of VPP startup.conf settings applied to all tests:

  1. heap-size - set separately for ip4, ip6, stats, main depending on scale tested.
  2. no-tx-checksum-offload - disables UDP / TCP TX checksum offload in DPDK. Typically needed for use faster vector PMDs (together with no-multi-seg).
  3. buffers-per-numa - sets a number of memory buffers allocated to VPP per CPU socket. VPP default is 16384. Needs to be increased for scenarios with large number of interfaces and worker threads. To accommodate for scale tests, CSIT is setting it to the maximum possible value corresponding to the limit of DPDK memory mappings (currently 256). For Xeon Skylake platforms configured with 2MB hugepages and VPP data-size and buffer-size defaults (2048B and 2496B respectively), this results in value of 215040 (256 * 840 = 215040, 840 * 2496B buffers fit in 2MB hugepage).

Per Test Settings #

List of vpp startup.conf settings applied dynamically per test:

  1. corelist-workers <list_of_cores> - list of logical cores to run VPP worker data plane threads. Depends on HyperThreading and core per test configuration.
  2. num-rx-queues - depends on a number of VPP threads and NIC interfaces.
  3. no-multi-seg - disables multi-segment buffers in DPDK, improves packet throughput, but disables Jumbo MTU support. Disabled for all tests apart from the ones that require Jumbo 9000B frame support.
  4. UIO driver - depends on topology file definition.
  5. QAT VFs - depends on NRThreads, each thread = 1QAT VFs.