Notifying network applications of receive overflow conditions
A method for notifying a packet destination that includes receiving a packet by a network interface card (NIC), where the packet destination is a destination of the packet, classifying the packet, forwarding the packet to one of a plurality of receive rings on the NIC, determining whether the one of the plurality of receive rings comprises space to store the packet, dropping the packet if the receive ring does not comprise the space to store the packet, and sending a notification message to the packet destination, where the notification message indicates that the packet was dropped by the receive ring.
1. A system, comprising:
a physical network interface card (NIC) comprising:
a plurality of receive rings;
a hardware classifier;
wherein the physical NIC is configured to:
receive a packet, wherein a packet destination is a destination of the packet,
classify the packet by the hardware classifier,
forward the packet to one of the plurality of receive rings,
determine whether the one of the plurality of receive rings comprises space to store the packet;
upon determining that the one of the plurality of receive rings does not comprise space to store the packet:
drop the packet;
increment a drop counter associated with the one of the plurality of receive rings; and
send a notification message from the physical NIC to the packet destination only if the drop counter exceeds a predefined notification threshold,
wherein the predefined notification threshold is a numeric value corresponding to a plurality of dropped packets,
wherein the notification message indicates that the packet was dropped by the one of the plurality of receive rings;
a host, operatively connected to the NIC, comprising:
the packet destination,
wherein the host is configured to forward the notification message to the packet destination; and
a virtual network interface card (VNIC) associated with the packet destination;
wherein the VNIC is configured to:
receive at least one packet,
determine whether the VNIC comprises space store the at least one packet,
dropping the at least one packet if the VNIC does not comprise space to store the at least one packet, and
send a second notification message to the packet destination,
wherein the second notification message indicates that the at least one packet was dropped by the VNIC.
2. The system of claim 1 , wherein the host is further configured to:
reset the drop counter associated with the one of the plurality of receive rings after the notification message is sent to the packet destination.
3. The system of claim 1 , wherein the notification message is sent from the physical NIC to the packet destination on the host using an out-of-band communication channel between the physical NIC and the packet destination on the host.
4. The system of claim 3 , wherein the out-of-band communication channel is a different communication path than a path used by incoming packets.