Reliable, out-of-order transmission of packets
A computing system supporting reliable network communications can include a virtual machine executing a user application, and a network adapter device coupled to the virtual machine via a plurality of virtual interfaces. The user application can communicate with the network adapter device using a virtual interface assigned to the user application. Queue pairs, each including a send queue and a receive queue, can be implemented to process transmit packets being sent from the virtual machine to the network and incoming packets being sent to the virtual machine from the network.
1 . A computing system, comprising:
a virtual machine executing a user application;
a network adapter device coupled to the virtual machine via a plurality of virtual interfaces, wherein the user application communicates with the network adapter device using a virtual interface assigned to the user application; and
a plurality of queue pairs each including a send queue and a receive queue,
wherein the user application is operable to place a message for transmission to a destination with an address handle associated with the destination in the send queue of a queue pair assigned to the user application, and
wherein the network adapter device is operable to:
identify a transport context for the destination based on the address handle, the transport context identifying a port of the network adapter device; and
transmit the message from the identified port to the destination via a network over multiple paths associated with the transport context for the destination,
wherein the transport context limits a number of outstanding packets on each of the multiple paths between the identified port and the destination.
2 . The computing system of claim 1 ,
wherein the virtual interface assigned to the user application is associated with an internet protocol (IP) address, and the queue pair assigned to the user application is associated with a queue pair identifier, and
wherein the IP address and the queue pair identifier are used as a sender address of the message.
3 . The computing system of claim 1 , wherein the transport context provides packet header information to route packets generated from the message for transmission to the destination.
4 . The computing system of claim 1 , wherein the network adapter device is operable to receive, from the network, packets containing a source address of a source, and identify a transport context associated with the source by indexing into a network address map using the source address.
5 . The computing system of claim 4 , wherein the transport context associated with the source is operable to place data from the received packets into a receive queue of a queue pair identified by a queue pair identifier included in the received packets.
6 . The computing system of claim 5 , wherein the network adapter device is operable to place the data from the receive queue into a buffer of a host memory of the computing system using direct memory access.
7 . The computing system of claim 6 , wherein the data from the receive queue are placed out of order in the buffer of the host memory.
8 . The computing system of claim 7 , wherein a driver program is operable to reorder the data from the buffer into a correct sequence.
9 . The computing system of claim 1 , wherein the plurality of queue pairs includes a queue pair reserved for management messages used for setting up or taking down connections.
10 . The computing system of claim 1 , wherein the plurality of queue pairs includes multiple queue pairs that are used by the user application.
11 . The computing system of claim 1 , wherein the plurality of virtual interfaces includes a virtual interface shared by multiple applications executing in the virtual machine.
12 . A network adapter device, comprising:
one or more processing cores;
a network interface;
a plurality of queue pairs; and
a plurality of transport contexts,
wherein upon a message being placed by a virtual machine into a send queue of a queue pair for transmission to a destination, the one or more processing cores are operable to:
identify a transport context for the destination based on an address handle of the message, the transport context identifying a port of the network adapter device; and
transmit the message from the identified port to the destination via the network interface on multiple paths associated with the transport context for the destination,
wherein the transport context limits a number of outstanding packets on each of the multiple paths between the identified port and the destination.
13 . The network adapter device of claim 12 , wherein the transport context for the destination provides packet header information to route packets generated from the message for transmission to the destination.
14 . The network adapter device of claim 12 , wherein upon receiving, from the network interface, packets containing a source address of a source, the one or more processing cores are operable to identify a transport context for the source by indexing into a network address map using the source address.
15 . The network adapter device of claim 14 , wherein the transport context of the source is operable to place data from the received packets into a receive queue of a queue pair identified by a queue pair identifier included in the received packets.
16 . The network adapter device of claim 15 , wherein the data from the receive queue are placed into a buffer of a host memory of a host system using direct memory access.
17 . The network adapter device of claim 16 , wherein the data from the receive queue are placed out of order in the buffer of the host memory.
18 . A method comprising:
receiving, at a send queue of a queue pair of a network adapter device, a message from a virtual machine for transmission to a destination;
identifying a transport context for the destination based on an address handle of the message, the transport context identifying a port of the network adapter device;
generating transmit packets from the message using header information provided by the transport context for the destination; and
sending the transmit packets from the identified port to the destination via a network on multiple paths associated with the transport context for the destination,
wherein the transport context limits a number of outstanding packets on each of the multiple paths between the identified port and the destination.
19 . The method of claim 18 , further comprising:
receiving, from the network, incoming packets containing a source address of a source;
identifying a transport context for the source by indexing into a network address map using the source address; and
placing data from the incoming packets into a receive queue of a queue pair identified by a queue pair identifier included in the incoming packets.
20 . The method of claim 19 , further comprising:
placing the data out of order from the receive queue into a buffer of a host memory using direct memory access; and
reordering the data from the buffer before providing the data to a user application.