Virtual-to-Physical Address Translation Using Virtual Address Index Bits
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Solution Overview
Problem
Conventional memory management systems face challenges in improving system performance without increasing circuit area or lowering processing speed, particularly in virtual-to-physical address translation systems that require numerous comparator circuits for efficient lookup.
Innovation Solution
A virtual-to-physical address translation system that uses a part of the virtual address as an index to store and retrieve translations, reducing the need for comparator circuits by utilizing a dual storage space architecture with buffer entries and translation entries, allowing for efficient storage and retrieval of virtual-to-physical address translations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the number of entries of the TLB is increased to improve system performance, then the system performance is improved, but the circuit area of the TLB increases, thus lowering processing speed
Solution Approach 1:
The patent segments the virtual address into multiple parts (index bits and tag bits) to organize TLB entries. The index bits directly address specific entry groups, while tag bits are used for comparison within groups. This segmentation allows the TLB to be divided into multiple smaller sets, reducing the circuit area required for each set while maintaining overall capacity and performance.
2Productivity
If the number of entries of the TLB is increased to improve system performance, then the system performance is improved, but the processing speed is lowered
Solution Approach 1:
By segmenting the TLB into multiple sets with direct indexing, the patent enables parallel access to different entry groups. This reduces the time required for address translation lookups, maintaining high processing speed even as the total number of entries increases to improve system performance.
3Area of stationary object
If the number of entries of the TLB is decreased, then the circuit area is reduced, but the system performance is degraded
Solution Approach 1:
The patent introduces a new dimension for organizing TLB entries by using multiple sets indexed by different bit positions of the virtual address. This dimensional organization allows the system to maintain a large effective capacity across multiple smaller physical sets, achieving high system performance with reduced circuit area compared to a single large associative memory structure.
4Measurement precision
If fully-associative mapping is used with multiple comparator circuits, then the lookup accuracy is improved, but the circuit area increases
Solution Approach 1:
The patent segments the comparison operation into two stages: first, the index bits directly address specific entry groups, eliminating the need for comparators to search all entries; second, tag bits are compared within each group to ensure accurate matching. This segmentation maintains lookup accuracy while dramatically reducing the number of comparator circuits required compared to fully-associative mapping.
Data Source
AI summary
A management method of a virtual-to-physical address translation system includes the following steps: providing a first storage space, wherein the first storage space includes a plurality of buffer entries; providing a second storage space, wherein the second storage space includes a plurality of translation entries, and the translation entries correspond to a plurality of translation indices; and when receiving a write instruction to write a first virtual-to-physical address translation into a specific buffer entry of the buffer entries, storing the first virtual-to-physical address translation in a write translation entry of the translation entries according to a first part of bits of a first virtual address corresponding to the first virtual-to-physical address translation, and storing the first virtual address and a write translation index corresponding to the write translation entry in the specific buffer entry.