Multi-Root PCI Express Switch Virtual Tree Boot
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Solution Overview
Problem
Conventional MRA PCI express switches require significant time to boot root complexes due to the need to grasp connection topologies and I/O types, leading to decreased system operability and complex reset and power management.
Innovation Solution
A multi-root PCI express switch with a virtual switch bridge controller that establishes a virtual PCI tree before booting, allowing root complexes to start without waiting for connection status grasping, and synchronizes this with a real PCI tree post-boot.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the MRA PCI express switch waits to grasp connection topology and I/O types before booting, then the PCI tree configuration is accurate, but the system boot time becomes excessively long
Solution Approach 1:
The patent applies preliminary action by establishing a preliminary PCI tree structure using default configuration information before the actual connection topology is known. The switch controller creates this preliminary structure in advance, allowing the system to boot without waiting for complete topology discovery. Later, the preliminary structure is updated to match the actual connection state, thus resolving the contradiction between boot speed and configuration accuracy.
2Reliability
If the MRA PCI express switch requires complete topology discovery before establishing PCI tree, then the configuration is reliable, but the reset and power management becomes complex
Solution Approach 1:
The patent segments the PCI tree establishment process into two independent phases: (1) preliminary structure creation using default information, and (2) later updates based on actual topology discovery. This segmentation allows the system to separate the boot process from the configuration refinement process, simplifying reset and power management while maintaining reliability through the two-stage approach.
3Manufacturing precision
If the system waits for connection status grasping before booting root complexes, then the PCI tree structure is accurate, but the system operability decreases
Solution Approach 1:
The system performs preliminary action by creating a default PCI tree structure before connection status is fully known, enabling root complexes to boot immediately. The structure is then refined later to match actual connections, thus improving system operability while maintaining tree structure accuracy through the two-stage configuration process.
Data Source
AI summary
Provided is an MRA (multi-root aware) PCI express switch accommodating a plurality of root complexes. The MRA PCI express switch includes: a setting register storing necessary information to set a PCI tree based on a switch connection topology and a physical connection state; and a virtual switch bridge controller storing necessary information to establish a virtual PCI tree, irrespective of a status of the setting register. The root complexes can be booted based on the information in the virtual switch bridge controller.