Directed SMI Handling for Multi-Core Processor Idle Management
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Solution Overview
Problem
The implementation of System Management Mode (SMM) in multi-processor systems is hindered by the need to synchronize all processor cores, leading to extended turnaround times and reduced availability of server RAS features due to constant time-sharing with OS cores, which is inefficient and less attractive for meeting application service level agreements.
Innovation Solution
Directed SMI handling is performed at idle processor cores, allowing individual cores to enter SMM during idle periods, with operations delayed until a subsequent SMI, thereby increasing CPU time slices for SMM mode execution and optimizing platform management scenarios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If all processor cores are synchronized to concurrently enter SMM mode, then system management operations can be performed, but the time required for SMM entry/exit significantly increases and processors are taken away from useful OS operation
Solution Approach 1:
The patent divides the system management operations into separate tasks that can be executed by different processor cores independently. Instead of synchronizing all cores to enter SMM simultaneously, individual cores can enter and exit SMM at different times based on their specific management tasks, thereby reducing the total time processors are unavailable for OS operations while still completing all necessary system management functions
Solution Approach 2:
The patent implements a dynamic approach where processor cores can transition to and from SMM mode flexibly based on operational needs rather than following a rigid synchronized schedule. The system allows cores to enter SMM when needed for specific management tasks and return to OS operation when complete, optimizing the balance between system management completion and OS availability
2Productivity
If processor cores are held invisible from the OS for extended periods to complete SMM operations, then platform management tasks can be finished, but OS timing requirements are violated and service level agreements cannot be met
Solution Approach 1:
The patent segments platform management tasks into smaller sub-tasks that can be completed in shorter time intervals. By dividing the overall management workload across multiple smaller SMM operations rather than one long continuous operation, the system can meet OS timing requirements while still accomplishing all necessary platform management functions
Solution Approach 2:
The patent implements periodic SMM operations where processor cores alternate between SMM mode for platform management tasks and OS mode for application workloads. This periodic switching allows the system to dedicate CPU time to both system management and OS operations in a rhythm that satisfies OS timing constraints while progressively completing management tasks
3Productivity
If time sharing is used between OS stack and platform management on the same cores, then processor utilization is maintained, but SMM operations take hours to complete due to constant context switching
Solution Approach 1:
The patent separates platform management tasks from OS operations by dedicating specific processor cores to SMM execution when needed. Instead of time-sharing the same cores between OS and management tasks, the system can allocate entire cores to complete management operations without context switching, then return them to the OS pool, thereby reducing SMM operation duration while maintaining overall processor utilization
Solution Approach 2:
The patent enables continuous execution of SMM operations on designated processor cores without interruption from OS context switching. By allowing cores to remain in SMM mode for the duration of management tasks rather than repeatedly switching in and out, the system eliminates the hours-long completion times caused by constant time-sharing while still maintaining high overall processor utilization through proper task scheduling
Data Source
AI summary
A method is described. The method includes determining that a first of a plurality of processor cores in a multi-processor computing system has entered an idle state, triggering a SMI for the first processor core, the first processor core entering a system management mode (SMM) and performing one or more platform management operations.