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Michael S. Tsirkin authored
Even when vhost-net is in zero-copy transmit mode, net core might still decide to copy the skb later which is somewhat slower than a copy in user context: data copy overhead is added to the cost of page pin/unpin. The result is that enabling tx zero copy option leads to higher CPU utilization for guest to guest and guest to host traffic. To fix this, suppress zero copy tx after a given number of packets triggered late data copy. Re-enable periodically to detect workload changes. Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
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