PCI express transaction descriptor
First Claim
1. An apparatus comprising:
- an I/O module to;
receive a packet of a transaction over an interconnect from a device, andidentify a hint from a particular header field of the packet, wherein the particular header field is to be included in a transaction descriptor of a header of the packet,the hint to indicate an intended use of data in a memory associated with the transaction, the header is to comprise at least two bytes, byte zero comprises a first of the at least two bytes, byte one is to be adjacent to byte zero, and the particular header field is to be included in byte one of the header and is to indicate the presence of the hint in the 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
39 Claims
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1. An apparatus comprising:
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an I/O module to; receive a packet of a transaction over an interconnect from a device, and identify a hint from a particular header field of the packet, wherein the particular header field is to be included in a transaction descriptor of a header of the packet, the hint to indicate an intended use of data in a memory associated with the transaction, the header is to comprise at least two bytes, byte zero comprises a first of the at least two bytes, byte one is to be adjacent to byte zero, and the particular header field is to be included in byte one of the header and is to indicate the presence of the hint in the packet. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. An apparatus comprising:
an I/O module to; insert a hint into at least one packet of a transaction, wherein the packet is to comprise a header, the header is to comprise at least two bytes, the hint is identifiable from a value of a particular header field in a transaction descriptor to the included in the header of the packet, byte zero is a first of the at least two bytes, byte one is a second of the at least two bytes, byte one is adjacent to byte zero, the particular field is to be included in byte one of the header, and the hint is to indicate an intended use of data in a memory associated with the transaction; and send the packet to a device over an interconnect. - View Dependent Claims (15, 16, 17, 18)
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19. An apparatus comprising:
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a root controller including an I/O module configured to receive a packet from a device over a Peripheral Component Interconnect Express (PCIe)-compliant interconnect, wherein the I/O module is to include a protocol stack including a transaction layer, a link layer, and a physical layer, the packet is to include a transaction layer header and a data payload, the transaction layer header is to include a transaction descriptor, the transaction layer header is to comprise at least two bytes, byte zero comprises a first of the at least two bytes, byte one is to be adjacent to byte zero, the transaction descriptor is to include one or more attribute fields, and a particular one of the attribute fields is to identify a hint and is to be included in byte one of the transaction layer header, wherein the packet is associated with a request of cache data and the hint is to indicate an intended use of the cache data and the cache data is to be identifiable from the hint.
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20. A method comprising:
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defining a hint for a transaction; generating a packet to include a header with a transaction descriptor including a plurality of attribute fields, wherein the header comprises at least two bytes, byte zero comprises a first of the at least two bytes, byte one is adjacent to byte zero, a particular attribute field of the transaction descriptor identifies the hint, and the particular attribute field is included in byte one; and sending the packet in the transaction using a Peripheral Component Interconnect Express (PCIe)-compliant interconnect, wherein the transaction includes a request of a memory; wherein the hint indicates an intended use of the memory. - View Dependent Claims (21, 22, 23, 24, 25, 26)
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27. A system comprising:
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a first device; a second device to; receive a transaction request from the first device using a Peripheral Component Interconnect Express (PCIe)-compliant interconnect, wherein the interconnect includes a transaction layer and the transaction request includes a request of a memory; and identify a hint from a particular field of a transaction descriptor of a header included in the transaction request, wherein the header is to comprise at least two bytes, byte zero comprises a first of the at least two bytes, byte one is to be adjacent to byte zero, the hint is to indicate an intended use of the memory by the first device, and the particular field is to be included in byte one of the header. - View Dependent Claims (28, 29, 30, 31)
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32. An apparatus comprising:
logic to; receive a packet, wherein the packet comprises a header, the header is to include a transaction descriptor that is to include a transaction identifier and a hint field, the header is to comprise at least two bytes, byte zero comprises a first of the at least two bytes, byte one is to be adjacent to byte zero, the packet is to be received over a Peripheral Component Interconnect Express (PCIe)-compliant interconnect and the hint field is to be included in byte one of the header; and service the packet to identify an intended use of a memory based at least in part on a value of the hint field. - View Dependent Claims (33, 34, 35)
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36. An apparatus comprising:
logic to; generate a packet to include a header, wherein the header is to include a transaction descriptor that is to include a transaction identifier and a hint field, the header is to comprise at least two bytes, byte zero comprises a first of the at least two bytes, byte one is to be adjacent to byte zero, the hint field is to be included in byte one of the header and is to indicate the presence of a hint included in the packet, the hint is to identify an intended use of a memory based at least in part on a value of the hint field; and send the packet to a device over a Peripheral Component Interconnect Express (PCIe)-compliant interconnect. - View Dependent Claims (37, 38, 39)
Specification