Method and apparatus for offloading message segmentation to a network interface card
One embodiment of the present invention provides a system that facilitates offloading message segmentation from a central processing unit onto a network interface card. The system operates by first receiving a TSO-send message at the network interface card, wherein the TSO-send message contains information about the message to be sent. Next, the system uses a header address from the TSO-send message to access a message header from memory using remote direct memory access. The system then uses a payload address from the TSO-send message to access a payload from memory that contains message data using remote direct memory access. Finally, the network interface card segments the payload into a set of maximum segment size (mss) segments and transmits the set of mss segments on the network.
1. A method for offloading message segmentation from a central processing unit to a network interface card, comprising:
receiving a Message send packet at the network interface card from the central processing unit, wherein the Message send packet contains information about a message to be sent, and wherein the information about the message to be sent includes an address to a message header, an address to a message data block to be transmitted, and a maximum segment size;
using the header address from the Message send packet to access the message header from memory using remote direct memory access;
using the address to the message data block from the Message send packet to access a payload containing message data from memory using remote direct memory access;
segmenting the payload into a set of maximum segment size segments; and
transmitting the payload on a network by transmitting the set of maximum segment size segments.
2. The method of claim 1 , wherein the Message send packet includes a maximum segment size that has been negotiated by a Transmission Control Protocol (TCP) stack.
3. The method of claim 1 , wherein segmenting the payload involves updating Internet Protocol (IP) parameters and Transmission Control Protocol (TCP) parameters for each segment.
4. The method of claim 1 , wherein the Message send packet includes a data length for the payload.
5. The method of claim 1 , wherein if a last segment of the payload is less than a specified minimum size, the method further comprises padding the last segment with bytes until it is at least the specified minimum size.
6. The method of claim 1 , further comprising processing a segment acknowledge message for each segment.
7. The method of claim 6 , further comprising sending an acknowledge message to a Transmission Control Protocol (TCP) stack that originated the Message send packet after receiving the segment acknowledge message for each segment.
8. The method of claim 1 , wherein the message header includes an Ethernet header, an Internet Protocol (IP) header, and a Transmission Control Protocol (TCP) header for the message.
9. A computer-readable storage medium storing instructions that when executed by a computer cause the computer to perform a method for offloading message segmentation from a central processing unit to a network interface card, the method comprising:
receiving a Message send packet at the network interface card from the central processing unit, wherein the Message send packet contains information about a message to be sent, and wherein the information about the message to be sent includes an address to a message header, an address to a message data block to be transmitted, and a maximum segment size;
using the header address from the Message send packet to access the message header from memory using remote direct memory access;
using the address to the message data block from the Message send packet to access a payload containing message data from memory using remote direct memory access;
segmenting the payload into a set of maximum segment size segments; and
transmitting the payload on a network by transmitting the set of maximum segment size segments.
10. The computer-readable storage medium of claim 9 , wherein the Message send packet includes a maximum segment size that has been negotiated by a Transmission Control Protocol (TCP) stack.
11. The computer-readable storage medium of claim 9 , wherein segmenting the payload involves updating Internet Protocol (IP) parameters and Transmission Control Protocol (TCP) parameters for each segment.
12. The computer-readable storage medium of claim 9 , wherein the Message send packet includes a data length for the payload.
13. The computer-readable storage medium of claim 9 , wherein if a last segment of the payload is less than a specified minimum size, the method further comprises padding the last segment with bytes until it is at least the specified minimum size.
14. The computer-readable storage medium of claim 9 , the method further comprising processing a segment acknowledge message for each segment.
15. The computer-readable storage medium of claim 14 , the method further comprising sending an acknowledge message to a Transmission Control Protocol (TCP) stack that originated the Message send packet after receiving the segment acknowledge message for each segment.
16. The computer-readable storage medium of claim 9 , wherein the message header includes an Ethernet header, an Internet Protocol (IP) header, and a Transmission Control Protocol (TCP) header for the message.
17. An apparatus for offloading message segmentation from a central processing unit to a network interface card, comprising:
a receiving mechanism that is configured to receive a Message send packet at the network interface card from the central processing unit, wherein the Message send packet contains information about a message to be sent, and wherein the information about the message to be sent includes an address to a message header, an address to a message data block to be transmitted, and a maximum segment size;
an accessing mechanism that is configured to use the header address from the Message send packet to access the message header from memory using remote direct memory access;
wherein the accessing mechanism is further configured to use address to the message data block from the Message send packet to access a payload containing message data from memory using remote direct memory access;
a segmenting mechanism that is configured to segment the payload into a set of maximum segment size segments; and
a transmitting mechanism that is configured to transmit the payload on a network by transmitting the set of maximum segment size segments.
18. The apparatus of claim 17 , wherein the Message send packet includes a maximum segment size that has been negotiated by a Transmission Control Protocol (TCP) stack.
19. The apparatus of claim 17 , wherein the segmenting mechanism is further configured to update Internet Protocol (IP) parameters and Transmission Control Protocol (TCP) parameters for each segment.
20. The apparatus of claim 17 , wherein the Message send packet includes a data length for the payload.
21. The apparatus of claim 17 , further comprising a padding mechanism that is configured to pad a last segment with bytes until it is at least a specified minimum size.
22. The apparatus of claim 17 , further comprising a processing mechanism that is configured to process a segment acknowledge message for each segment.
23. The apparatus of claim 22 , further comprising a sending mechanism that is configured to send an acknowledge message to a Transmission Control Protocol (TCP) stack that originated the Message send packet after receiving the segment acknowledge message for each segment.
24. The apparatus of claim 17 , wherein the message header includes an Ethernet header, an Internet Protocol (IP) header, and a Transmission Control Protocol (TCP) header for the message.