Network Interface Controller Sleep State Traffic Management
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Solution Overview
Problem
Large-scale computer systems face challenges in reducing power consumption during idle periods, as existing power management techniques either discard incoming traffic or require costly buffering to maintain network connectivity, leading to wasted bandwidth and performance issues.
Innovation Solution
A method and apparatus for peripheral devices, such as network interface controllers, to receive notifications of host resource sleep states and send messages to data sources to defer data transmission until the host resources awaken, using negative acknowledgments or congestion notifications to manage packet traffic and optimize sleep states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by stationary object
If the host processor enters sleep states to reduce power consumption, then power consumption is reduced, but incoming network traffic may be lost or require costly buffering
Solution Approach 1:
The patent introduces an intermediary mechanism where the network interface controller autonomously manages incoming traffic during host sleep states. Instead of directly losing packets or requiring expensive buffers, the NIC acts as a mediator that detects sleep states, sends hold-off messages to data sources, and coordinates traffic resumption, thereby preserving both power savings and network reliability
Solution Approach 2:
The system performs preliminary actions by notifying data sources of upcoming sleep states before they occur. The host processor or NIC sends advance notification to data sources, allowing them to pause transmission proactively. This prevents data loss without requiring buffering, as the action is taken before the sleep state begins
2Reliability
If data is buffered during host sleep states to maintain network connectivity, then network connectivity is maintained, but power consumption increases due to costly buffering resources
Solution Approach 1:
The patent extracts the traffic management function from the host processor and places it in the network interface controller. By taking out the autonomous decision-making capability from the main system, the host can sleep without requiring active buffering resources, while the NIC handles traffic coordination independently, eliminating the need for expensive buffers during sleep states
Solution Approach 2:
The network interface controller provides self-service by autonomously managing incoming traffic during host sleep states. It independently detects sleep states, communicates with data sources to hold off transmission, and resumes traffic upon host awakening without requiring host processor intervention or expensive buffering resources
3Speed
If the peripheral device sends interrupt to wake the host processor immediately upon receiving data, then data processing is prompt, but sleep state duration is reduced increasing power consumption
Solution Approach 1:
The system performs preliminary notification to data sources about upcoming sleep states before the host actually enters them. By advance‑notifying the data source of the projected sleep period, the peripheral device can defer interrupts until the sleep period ends, allowing the host to maintain its sleep state longer while still ensuring timely data handling after awakening
Solution Approach 2:
The interrupt timing is made dynamic rather than fixed. The peripheral device adapts interrupt behavior based on host power state - sending interrupts immediately when the host is active, but deferring them until after sleep periods. This dynamic adjustment optimizes both response time and power consumption based on current system state
4Productivity
If the host processor remains active to handle incoming traffic promptly, then network performance is maintained, but power consumption increases
Solution Approach 1:
The network interface controller provides self-service by autonomously managing incoming traffic during host sleep states. It independently detects sleep states, communicates with data sources to hold off transmission, and resumes traffic upon host awakening without requiring host processor intervention or expensive buffering resources
Solution Approach 2:
The system uses periodic or event-driven host activity patterns to determine when to sleep. The host alternates between active and sleep states based on workload, and the NIC coordinates traffic accordingly - allowing the host to remain active during high‑performance periods and sleep during low‑activity periods, optimizing both performance and power consumption
Data Source
AI summary
A method for processing data includes receiving in a peripheral device, which is connected by a bus to a host processor having host resources, a notification of a sleep state of at least one of the host resources. While the at least one of the host resources is in the sleep state, when the peripheral device receives data from a data source for delivery to the host processor, the peripheral device sends a message to the data source, which causes the data source to defer conveying further data to the peripheral device until the at least one of the host resources has awakened from the sleep state.