Nvidia Corporation

Hitendra Dutt

Wei-Je Robert Huang

Michael Hopgood

Vishal Mehta

David Wyatt

Mark Taylor

Mohammad Shafiul Mobin

Vishnu Balan

Dennis K Ma

Eric Tyson

Robert Huang

Samuel Vincent

In a computing system, various components/devices communicate with each other. For example, a microprocessor may communicate with memory or may communicate with another microprocessor over a link. Various factors such as the frequency and transmission speed of a signal can distort what is being communicated over a link. The problem becomes more pronounced as the transmission speed increases. To address this problem, devices on both ends of a link can cooperate to equalize the link. Equalization involves configuring the transmitting device to alter the signal being transmitted so that certain distortions introduced during transmission are negated by the time the signal arrives at the receiving device. Given that each link can have slightly different characteristics, appropriate equalization parameters need to be ascertained for each link. Introduced herein are improved techniques for performing equalization that are quick yet provide equalization parameters that are stable even in a noisy high-speed link.

Techniques for improving high-speed communications in a computing system

A method comprises selecting a starting point on a map of equalization coefficients and measuring an eye height of a signal transmitted using the set of equalization coefficients associated with the starting point and an eye height associated with each adjacent point on the map relative to the starting point. The eye height associated with an adjacent point is based on a signal transmitted using the set of equalization coefficients associated with the adjacent point. The method also comprises walking on the map in a first direction from the starting point to the adjacent point associated with the greatest eye height, wherein the eye height associated with the adjacent point is greater than or equal to the eye height associated with the starting point.

Equalization coefficient search algorithm

In a system according to one embodiment of the present disclosure, the system comprises a first device, a second device, a communications link, and a memory. The memory stores instructions that when executed by the system perform a method of communications link training. This method comprises requesting a speed change to a second speed for the first device communicating with the second device at a first speed via the communications link. A saved set of parameters are accessed for at least one of the first device and the second device. A first training cycle is performed for the first device and the second device at the second speed using the saved set of parameters for the at least one of the first device and second device. The reuse of parameters from a previous successful equalization training cycle reduces the time required to perform equalization training.

System and method for detecting reuse of an existing known high-speed serial interconnect link

A processing unit exchanges data with another processing unit across a data connector that supports a particular communication protocol. When the communication protocol is updated to support a new packet type, a specification of that new packet type may be stored within software registers included within the processing unit. Under circumstances that require the use of the new packet type, packet generation logic may read the packet specification of the new packet type, then generate and transmit a packet of the new type.

System and method for sending arbitrary packet types across a data connector

In an apparatus according to one embodiment of the present disclosure, a communications link comprises a first device and a second device communicating with each other via the communications link at a plurality of different speeds. However, prior to communicating via the communications link for the first time at a second speed, the first device and second device complete a first training cycle at the second speed. Further, during this first training cycle for the second speed, the first training cycle for the second speed will pause before the first training cycle at the second speed completes, and the first device and second device communicate at a first speed for a period of time before returning to the paused first training cycle at the second speed. When the paused first training cycle for the second speed continues, the first training cycle for the second speed will continue where it had paused.

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Sunnyvale, CA, United States of America

Hitendra Dutt