Large Receive Offload

Use Large Receive Offload (LRO) to reduce the CPU overhead for processing packets that arrive from the network at a high rate.

LRO reassembles incoming network packets into larger buffers and transfers the resulting larger but fewer packets to the network stack of the host or virtual machine. The CPU has to process fewer packets than when LRO is disabled, which reduces its utilization for networking especially in the case of connections that have high bandwidth.

To benefit from the performance improvement of LRO, enable LRO along the data path on an ESXi host including VMkernel and guest operating system. By default, LRO is enabled in the VMkernel and in the VMXNET3 virtual machine adapters.

For information about the location of TCP packet aggregation in the data path, see VMware Knowledge Base article Understanding TCP Segmentation Offload (TSO) and Large Receive Offload (LRO) in a VMware environment.