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5.5. Batching Network Packets

In configurations with a long transmission path, batching packets before submitting them to the kernel may improve cache utilization.
To configure the maximum number of packets that can be batched where N is the maximum number of packets to batch:
# ethtool -C $tap rx-frames N
To provide support for tun/tap rx batching for type='bridge' or type='network' interfaces, add a snippet similar to the following to the domain XML file.
...
<devices>
  <interface type='network'>
    <source network='default'/>
    <target dev='vnet0'/>
      <coalesce>
        <rx>
          <frames max='7'/>
        </rx>
      </coalesce>
  </interface>
</devices>