Interrupt Controller Delay Logic for Power Management
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Solution Overview
Problem
Hardware blocks face significant energy and time costs when transitioning between active and non-active modes, particularly due to frequent wake-up and idle cycles, which is exacerbated by smaller technology dimensions leading to increased static energy leakage and heat generation, necessitating more efficient management of interrupts.
Innovation Solution
An interrupt controller that allows for delayed interrupts, enabling hardware blocks to activate only when necessary, thereby concentrating active time and reducing unnecessary transitions between modes by setting a specific time for activation based on the latest required handling of information, even if the receiving hardware block is in non-active mode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If hardware blocks frequently transition between active and non-active modes to save energy, then energy consumption is reduced, but wake-up time and energy overhead increase
Solution Approach 1:
The patent merges multiple interrupt requests into a single wake-up event. When multiple interrupts are pending and the hardware block is in non-active mode, the system consolidates these interrupts and wakes up the hardware block only once, allowing it to process all pending interrupts in sequence. This eliminates multiple wake-up transitions and reduces both energy consumption and wake-up time overhead.
Solution Approach 2:
The system performs preliminary action by pre-identifying and consolidating multiple pending interrupts before the hardware block wakes up. The interrupt controller detects pending interrupts while the hardware block is in non-active mode and prepares a consolidated wake-up signal, so that when the hardware block wakes up, it can immediately process all pending tasks without repeated wake-up cycles.
2Reliability
If interrupts are handled immediately upon receipt, then task deadlines are met, but energy consumption increases due to frequent mode transitions
Solution Approach 1:
The system dynamically adjusts interrupt handling behavior based on the activity state of the hardware block. When the hardware block is in non-active mode, interrupts are deferred and consolidated. When in active mode, interrupts are handled immediately. This dynamic adaptation ensures task deadlines are met during active periods while minimizing energy consumption during non-active periods.
Solution Approach 2:
The system changes the parameter of interrupt handling timing based on the hardware block's activity state. Instead of always handling interrupts immediately, the system modifies the interrupt handling parameter to defer processing until the hardware block is active, thereby reducing unnecessary mode transitions while still meeting task deadlines.
3Speed
If hardware blocks remain in active mode to handle interrupts immediately, then interrupt response time is reduced, but energy consumption increases due to static leakage
Solution Approach 1:
The patent merges multiple interrupt requests into a single wake-up event. When multiple interrupts are pending and the hardware block is in non-active mode, the system consolidates these interrupts and wakes up the hardware block only once, allowing it to process all pending interrupts in sequence. This eliminates multiple wake-up transitions and reduces both energy consumption and wake-up time overhead.
4Area of stationary object
If smaller technology dimensions are used to reduce hardware size, then device area is reduced, but static energy leakage and heat generation increase
Solution Approach 1:
The system employs periodic action by implementing duty cycling - hardware blocks alternately operate in active and non-active modes. During non-active periods, the hardware block is powered down to minimize static energy leakage. Interrupts are deferred and consolidated, and the hardware block wakes up periodically to process pending tasks, then returns to non-active mode. This periodic operation significantly reduces average power consumption and heat generation while maintaining functionality.
Data Source
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AI summary
Methods of operation and interrupt controllers for generating interrupt signals to a unit, which could enter an active mode and a non-active mode, are disclosed. The interrupt controllers have interrupt logic (204) adapted for receiving requests for interrupt, activity mode logic (202) adapted for receiving information whether the unit is in non-active mode, and delay control logic (203) adapted for delaying the interrupt to the unit when the received information indicates that the unit is in non-active mode.