Service Processor Adapter Ownership Transfer
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Solution Overview
Problem
Power management in multiple partition systems is complex, particularly with peripheral connections like Wake-On-LAN enabled Ethernet adapters, where complete system restart occurs upon power restoration, and ownership transfer between virtual machines is not feasible, leading to inefficient power management and potential unnecessary system wake-ups.
Innovation Solution
A method and system where a service processor manages power management events by generating signals to the hypervisor, allowing for controlled transfer of adapter ownership between virtual machines without complete system power restoration, using a transistor to manage standby power and simulate power cycles, enabling flexible Wake-On-LAN event handling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Wake-On-LAN detection circuitry is connected directly to the system power supply, then the adapter can detect wakeup signals, but the entire system must be restarted when power is restored
Solution Approach 1:
The patent segments the power management function by introducing a service processor that independently manages adapter power states. The service processor creates a power management event signal separate from the main system power supply, allowing the adapter to be powered up independently without restarting the entire system. This segmentation resolves the contradiction by enabling reliable wakeup detection while avoiding full system restart.
Solution Approach 2:
The service processor acts as an intermediary between the adapter's wakeup detection circuitry and the main system power supply. It receives the wakeup signal from the adapter, generates a power management event signal, and controls power restoration selectively. This intermediary mechanism allows the adapter to detect wakeup signals reliably while preventing unnecessary full system restarts.
2Reliability
If adapter ownership is fixed to a specific partition, then the partition has guaranteed access to the adapter, but the adapter cannot be transferred between virtual machines
Solution Approach 1:
The patent implements dynamic adapter ownership by allowing the hypervisor to transfer adapter control between different virtual machine partitions. The service processor manages power states dynamically, and the hypervisor can redirect adapter ownership based on current system needs. This dynamic mechanism maintains reliable adapter access for the owning partition while enabling flexible ownership transfer when required.
3Loss of energy
If the entire system is powered down, then power consumption is minimized, but the system cannot respond to wakeup events from low-priority partitions
Solution Approach 1:
The patent applies local quality by enabling different power management states for different partitions. The service processor tracks which partitions are in power-down state and which are active, allowing selective power restoration based on partition priority and wakeup event source. This allows the system to maintain low power consumption overall while being able to respond to wakeup events from specific partitions when necessary.
Data Source
AI summary
A method and system for managing peripheral connection wakeup signaling in a processing system supporting multiple virtual machines provides a mechanism by which ownership of a peripheral having system wakeup capability is transferred between virtual machines. The power management event signal is connected to a service processor input that in turn signals a hypervisor to direct the wakeup activity to a particular logical partition in which the virtual machine was last executing. The hypervisor can then determine whether or not to wake up the entire system, or portions thereof and can direct the power management event to the appropriate virtual machine. In particular the peripheral may be an Ethernet adapter supporting Wake-On-LAN capability. State initialization, which is typically ensured by system power cycling is provided instead by controlling power to the standby power source or in some instances by forcing an indication of a disconnect/reconnect of the wakeup signaling connection.