Throttling integrated link
Methods and apparatus for throttling an interface that is integrated on the same die as a processor are described. In one embodiment, a signal from an Integrated Input/Output hub (e.g., integrated on the same die as a processor) causes throttling of a link coupled between the IIO and an Input/Output (IO) device. Other embodiments are also disclosed.
1. A integrated circuit device comprising:
a processor; and
an Integrated Input/Output (IIO) logic coupled to the processor,
wherein a signal is to cause throttling of a link coupled between the IIO and an Input/Output (IO) device, wherein the link is one of a transmit link or a receive link, wherein throttling of the transmit link is to be performed by an on or off modulation, wherein the transmit link remains in an off state for a first duration, wherein the transmit link is to transmit an acknowledgement signal in response to receiving a packet and within a second duration from receiving the packet, wherein an upper link layer logic of the processor is to provide link support for upper link layer communication with the IIO logic, wherein separation of read and write pointers is configurable to account for clock skew differences between the upper link layer logic and the IIO logic, wherein the read and write pointers are to be reset in response to an indication that the processor and the IIO logic are awake.
2. The device of claim 1 , wherein the first duration or the second duration is a programmable duration.
3. The device of claim 1 , wherein during the first duration, the transmit link refrains from sending one or more acknowledgement signals for any packets received on the receive link.
4. The device of claim 1 , wherein during the first duration, the transmit link sends acknowledgement signals to avoid triggering of an error recovery at an endpoint of the link.
5. The device of claim 1 , wherein during the first duration, the transmit link exits the off state at a programmable interval, sends acknowledgement signals, and returns to the off state.
6. The device of claim 1 , wherein throttling of the receive link is performed by refraining from sending credits to the transmit link.
7. The device of claim 1 , wherein the transmit link enters the off state in response to lack of existing credits and detection of an idle state.
8. The device of claim 1 , wherein the processor comprises a plurality of processor cores.
9. The integrate circuit device of claim 1 , wherein the upper link layer logic includes one or more of: a virtual channel queue, flow control or credits logic, CRC (Cyclical Redundancy Check) check or generation logic, and parameter exchange logic.
10. A method comprising:
generating a signal to cause throttling of a link coupled between an IIO logic and an Input/Output (IO) device in response to detection of a temperature value at the link, wherein the link is to comprise a transmit link or a receive link,
wherein throttling of the transmit link is performed by an on or off modulation, wherein throttling of the transmit link is performed by an on or off modulation, wherein the transmit link remains in an off state for a first duration, wherein the transmit link transmits an acknowledgement signal during an on state in response to receiving a packet on the receive link and within a second duration from receiving the packet, wherein an upper link layer logic provides link support for upper link layer communication with the IIO logic, wherein separation of read and write pointers is configurable to account for clock skew differences between the upper link layer logic and the IIO logic, wherein the read and write pointers are reset in response to an indication that a processor and the IIO logic are awake.
11. The method of claim 10 , wherein the first duration or the second duration is a programmable duration.
12. The method of claim 10 , further comprising, during the first duration, the transmit link exiting the off state at a programmable interval, sending one or more acknowledgement signals, and returning to the off state.
13. The method of claim 10 , wherein throttling of the receive link is performed by refraining from sending credits to the transmit link and wherein the transmit link enters the off state in response to lack of existing credits and detection of an idle state.
14. The method of claim 10 , further comprising communicating data between a system memory and the I/O device via the IIO logic.
15. A system comprising:
a system memory to store data;
a processor to access the stored data; and
an Integrated Input/Output (IIO) logic coupled to the processor,
wherein a signal causes throttling of a point-to-point a link coupled between the IIO and an Input/Output (IO) device,
wherein data is communicated between the system memory and one or more I/O devices via the IIO logic, wherein the link is a transmit link or a receive link, wherein throttling of the transmit link is to be performed by an on or off modulation, wherein throttling of the transmit link is performed by an on or off modulation, wherein the transmit link remains in an off state for a first duration, wherein the transmit link transmits an acknowledgement signal during an on state in response to receiving a packet on the receive link and within a second duration from receiving the packet, wherein an upper link layer logic of the processor is to provide link support for upper link layer communication with the IIO logic, wherein separation of read and write pointers is configurable to account for clock skew differences between the upper link layer logic and the IIO logic, wherein the read and write pointers are to be reset in response to an indication that the processor and the IIO logic are awake.
16. The system of claim 15 , wherein the first duration or the second duration is a programmable duration.
17. The system of claim 15 , wherein during the first duration, the transmit link refrains from sending one or more acknowledgement signals for any packets received on the receive link.
18. The system of claim 15 , wherein during the first duration, the transmit link sends acknowledgement signals to avoid triggering of an error recovery at an endpoint of the link.
19. The system of claim 15 , wherein during the first duration, the transmit link exits the off state at a programmable interval, sends acknowledgement signals, and returns to the off state.
20. The system of claim 15 , wherein throttling of the receive link is performed by refraining from sending credits to the transmit link.
21. The system of claim 15 , wherein the transmit link enters the off state in response to lack of existing credits and detection of an idle state.