Idle Driven Network Scheduling with Dynamic Timer Control
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Solution Overview
Problem
Modern operating systems face challenges in balancing latency and overhead in network processing, particularly in scenarios with varying traffic levels or critical response times, as existing approaches fail to effectively manage timer mechanisms in these conditions.
Innovation Solution
The method involves using idle CPU time to control timer hardware, allowing network processing components to wake up based on load information and adjust sleep durations dynamically, ensuring optimal latency and overhead management by receiving interrupt signals from a timer and determining load information to select appropriate sleep durations for subsequent cycles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If hardware coalesces data at a set frequency to minimize latency, then response time improves, but overhead increases
Solution Approach 1:
The patent implements dynamic adjustment of timer interrupt frequencies based on real-time network traffic conditions and CPU load. The system transitions from static hardware-coalesced timing to adaptive software-controlled timing, where the interrupt frequency is modified according to actual traffic patterns, thereby optimizing the balance between latency and overhead
Solution Approach 2:
The system changes the timing parameters of timer interrupts dynamically based on traffic conditions. When traffic is heavy, the system increases interrupt frequency to reduce latency; when traffic is light, it decreases frequency to reduce overhead. This parameter adaptation resolves the contradiction by making the system responsive to actual conditions rather than operating at fixed settings
2Loss of energy
If interrupts are disabled and software polls on OS tick frequency, then overhead reduces, but latency increases
Solution Approach 1:
The patent introduces dynamic polling intervals that adapt to traffic conditions. Instead of using fixed OS tick frequencies, the system adjusts polling rates based on network traffic intensity and CPU availability, enabling the system to reduce overhead during low traffic while maintaining acceptable latency during high traffic periods
Solution Approach 2:
The system implements feedback mechanisms that monitor network traffic patterns and CPU load, then use this information to adjust interrupt and polling frequencies. This closed-loop control allows the system to optimize the trade-off between overhead and latency by responding to actual system conditions rather than operating with fixed parameters
3Productivity
If timer mechanism operates with fixed frequency, then heavy traffic handling improves, but critical response time to new work deteriorates
Solution Approach 1:
The patent implements dynamic timer frequency adjustment that responds to traffic conditions. When new work arrives requiring critical response, the system increases interrupt frequency to ensure timely processing. During sustained heavy traffic, it may use lower frequencies with larger coalescing windows. This dynamic behavior resolves the contradiction by adapting to different traffic patterns rather than using a single fixed frequency
Data Source
AI summary
A system and method of idle driven scheduling in a network device is disclosed. An interrupt signal is received from a timer, wherein a network processing component of a network device awakes from sleep mode of a first sleep duration for a first cycle upon receiving the interrupt signal. Load information of a computer processing unit in the network device for the first cycle is determined. A second sleep duration is selected for the network processing component in a second cycle based on the load information, wherein the second sleep duration is different from the first sleep duration. The timer is then instructed to send the interrupt signal to the network processing component at an expiration of the second sleep duration.