Transaction layer packet formatting
First Claim
1. An apparatus comprising:
- a receiver to receive a transaction layer packet from an input/output (I/O) device, wherein the I/O device comprises an add-in card, the transaction layer packet is to comprise a header, and the header is to comprise;
a first byte of the header,a second byte adjacent to the first byte, wherein the second byte is to include a hint field, and the hint field is to identify a hint in the transaction layer packet; and
a no-snoop attribute to be included in another byte of the header subsequent to the first byte; and
protocol circuitry to process the transaction layer packet.
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Abstract
A method and apparatus for enhancing/extending a serial point-to-point interconnect architecture, such as Peripheral Component Interconnect Express (PCIe) is herein described. Temporal and locality caching hints and prefetching hints are provided to improve system wide caching and prefetching. Message codes for atomic operations to arbitrate ownership between system devices/resources are included to allow efficient access/ownership of shared data. Loose transaction ordering provided for while maintaining corresponding transaction priority to memory locations to ensure data integrity and efficient memory access. Active power sub-states and setting thereof is included to allow for more efficient power management. And, caching of device local memory in a host address space, as well as caching of system memory in a device local memory address space is provided for to improve bandwidth and latency for memory accesses.
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Citations
27 Claims
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1. An apparatus comprising:
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a receiver to receive a transaction layer packet from an input/output (I/O) device, wherein the I/O device comprises an add-in card, the transaction layer packet is to comprise a header, and the header is to comprise; a first byte of the header, a second byte adjacent to the first byte, wherein the second byte is to include a hint field, and the hint field is to identify a hint in the transaction layer packet; and a no-snoop attribute to be included in another byte of the header subsequent to the first byte; and protocol circuitry to process the transaction layer packet. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. An apparatus comprising:
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a receiver to receive a transaction layer packet over a point-to-point interconnect, wherein the transaction layer packet is to correspond to a transaction and is to comprise a header, the header is to comprise a first byte of the header, a hint field is to be included in a second byte of the header adjacent to the first byte, and a transaction descriptor in another byte of the header subsequent to the second byte, the transaction descriptor is to comprise a no-snoop attribute, and the hint field is to identify a hint in the transaction layer packet; a layered protocol stack to comprise a transaction layer, a link layer, and a physical layer, wherein the layered protocol stack is implemented at least in part by protocol circuitry to identify a hint from the hint field; and coherency logic to identify, from the no-snoop attribute, whether snoop filtering applies to corresponding snoop requests of shared memory associated with the transaction.
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16. An apparatus comprising:
an interface to; interface with an add-in card; and send a transaction layer packet to the add-in card, wherein the transaction layer packet is to correspond to a transaction and is to comprise a header, the header is to comprise; a first byte of the header, a second byte of the header adjacent to the first byte, wherein the second byte is to include a hint field, and the hint field is to identify a hint in the transaction layer packet, and a transaction descriptor in another byte of the header subsequent to the second byte, wherein the transaction descriptor is to comprise a no-snoop attribute and the hint field is to identify a hint in the transaction layer packet.
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17. An apparatus comprising:
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protocol logic implemented at least in part in computing hardware, wherein the protocol logic is to; receive a transaction layer packet from an input/output (I/O) device, the transaction layer packet is to comprise a header, and the header is to comprise; a first byte of the header, a second byte of the header adjacent to the first byte, wherein the second byte is to include a hint field to identify a hint in the transaction layer packet, and a no-snoop attribute to be included in another byte of the header subsequent to the first byte; and process the transaction layer packet based at least in part on the hint and the no-snoop attribute. - View Dependent Claims (18)
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19. A method comprising:
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receiving a transaction layer packet over a point-to-point interconnect, wherein the transaction layer packet is to correspond to a transaction and is to comprise a header, the header is to comprise a first byte of the header, a second byte of the header adjacent to the first byte, and a transaction descriptor in another byte of the header subsequent to the second byte, wherein the second byte is to include a hint field to identify a hint in the transaction layer packet, the transaction descriptor is to comprise a no-snoop attribute, and the hint field is to identify a hint in the transaction layer packet; identifying a hint from the hint field; and determining whether to snoop a transaction based on the no-snoop attribute. - View Dependent Claims (20, 21)
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22. A system:
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a first device; and a second device comprising I/O circuitry to; receive a transaction layer packet from the first device over a point-to-point serial data link, wherein the transaction layer packet is to correspond to a transaction associated with shared memory; identify a hint field in a header of the transaction layer packet, wherein the header is to comprise a first byte and a second byte of the header adjacent to the first byte, and the hint field is to be included in the second byte; identify a no-snoop attribute in the header, wherein the no-snoop attribute is to be included in another byte of the header subsequent to the second byte. - View Dependent Claims (23, 24, 25)
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26. An apparatus comprising:
a connector to accept a card device, wherein the connector comprises logic to; receive a transaction layer packet from the card device, the transaction layer packet is to comprise a header, and the header is to comprise; a first byte of the header, a second byte adjacent to the first byte, wherein the second byte is to include a hint field, and the hint field is to identify a hint in the transaction layer packet; and a no-snoop attribute to be included in another byte of the header subsequent to the first byte. - View Dependent Claims (27)
Specification