PCI express enhancements and extensions
First Claim
1. An apparatus comprising:
- an input/output (I/O) module including a protocol stack configured to communicate with a device over a serial point-to-point interconnect, the protocol stack being configured to transmit a first packet on the serial point to point interconnect, wherein the first packet is to include a reference to a memroy address and a first caching hint including an intent to write only hint, and wherein in response to the first cache hint including the intent to write only, the device is not to fetch a data element from the memory address and is to transition a memory location associated with the memory address to an Exclusive coherency state.
0 Assignments
0 Petitions
Accused Products
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.
63 Citations
28 Claims
-
1. An apparatus comprising:
an input/output (I/O) module including a protocol stack configured to communicate with a device over a serial point-to-point interconnect, the protocol stack being configured to transmit a first packet on the serial point to point interconnect, wherein the first packet is to include a reference to a memroy address and a first caching hint including an intent to write only hint, and wherein in response to the first cache hint including the intent to write only, the device is not to fetch a data element from the memory address and is to transition a memory location associated with the memory address to an Exclusive coherency state. - View Dependent Claims (2, 3, 4)
-
5. An apparatus comprising:
an input/output (I/O) module configured to implement a protocol stack including at least a transaction layer, a link layer, and a physical layer, the I/O module configured to transmit a first packet, wherein the first packet is to include a reference to an address and a caching hint, and wherein in response to the caching hint indicating the element is to be fetched, an element associated with the address is to be fetched and held in a cache coherency state within a cache memory based on the caching hint. - View Dependent Claims (6, 7, 8, 9, 10)
-
11. An apparatus comprising:
an input/output (I/O) module including a protocol stack configured to communicate with a device over a serial point-to-point interconnect, the protocol stack being configured to transmit a first packet on the serial point to point interconnect, wherein the first packet is to include a reference to a memroy address and a first caching hint including an intent to read and write hint, and wherein in response to the first cache hint including the intent to read and write hint, the device is to fetch a data element from the memory address and is to transition a memory location to hold the data element to an Exclusive coherency state. - View Dependent Claims (12, 13, 14, 16, 17, 18)
-
15. An apparatus comprising:
an input/output (I/O) module including a protocol stack configured to communicate with a device over a serial point-to-point interconnect, the protocol stack being configured to transmit a first packet on the serial point to point interconnect, wherein the first packet is to include a reference to a memroy address and a first caching hint including an intent to read only hint, and wherein in response to the first cache hint including the intent to read only hint, the device is to fetch a data element from the memory address and is to transition a memory location to hold the data element to an Exclusive or Shared coherency state.
-
19. A method comprising:
-
transmiting a first packet with an input/output (I/O) module including a protocol stack over a serial point-to-point interconnect, the first packet including a reference to a memroy address and a first caching hint; determining if a data element associated with the memory address is to be fetched based on the first caching hint in response to receiving the first packet from the serial point-to-point interconnect; fetching the data element in response to determining the data element associated with the memory address is to be fetched based on the first caching hint; and transitioning a cache memory location associated with the memroy address to a cache coherency state based on the first caching hint. - View Dependent Claims (20, 21, 22, 23, 24)
-
-
25. A system comprising:
-
a transmitting device including an input/output (I/O) module configured to implement a protocol stack including at least a transaction layer, a link layer, and a physical layer, the I/O module being configured to transmit a first packet, wherein the first packet is to include a reference to an address and a caching hint a receiving device coupled to the transmitting device over a serial point-to-point interconnect, the receiving device including a cache memory, fetch logic, and an I/O module configured to implement a protocol stack, the I/O module being configured to receive the first packet, wherein the fetch logic is configured to determine if a data element is to be fetched from the address based on the caching hint and the cache memory is configured to hold a cache location associated with the address in a cache coherency state based on the caching hint. - View Dependent Claims (26, 27, 28)
-
Specification