Bulk Register Access Circuit Reducing Processor Fabric Overhead
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Solution Overview
Problem
Current processor communication protocols are inefficient due to high overhead in accessing multiple registers, especially when registers are not located at incremental addresses, leading to reduced fabric efficiency and increased latency in operations like power state transitions.
Innovation Solution
The introduction of bulk read and write messages that allow multiple registers to be accessed with a single message, using a compacted address format and a single header, reducing overhead and optimizing bus utilization by enabling efficient communication of register context between agents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If individual register access packets are used for each register read/write operation, then register access functionality is provided, but packet-based fabric overhead increases significantly reducing fabric efficiency
Solution Approach 1:
The patent combines multiple individual register access packets into a single bulk access packet that can read or write multiple registers simultaneously. This merging approach consolidates what would otherwise be multiple separate transactions with individual headers into one unified transaction, thereby reducing the total overhead consumption and improving fabric efficiency.
Solution Approach 2:
The bulk access packet structure is designed to serve multiple register access operations within a single packet. The packet can accommodate multiple register addresses and data transfers, making it a universal solution that replaces multiple specialized individual access packets with one multi-functional packet.
2Loss of time
If registers are accessed individually through packet-based communication, then register read/write operations are enabled, but latency increases for operations like power state transitions
Solution Approach 1:
By merging multiple register accesses into a single bulk packet operation, the patent reduces the cumulative latency that would result from sequential individual packet transmissions. This consolidation enables faster completion of time-sensitive operations such as power state transitions by performing multiple register reads or writes in parallel rather than sequentially.
3Ease of operation
If standard packet headers are used for each register access, then routing and packet identification is provided, but communication overhead increases
Solution Approach 1:
The patent segments the packet structure into a single shared header portion and multiple data portions. The header is reused for all register accesses within the bulk packet, eliminating the need for duplicate headers for each register. This segmentation maintains routing and identification capabilities while significantly reducing the total volume of header information transmitted.
Data Source
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AI summary
In one embodiment, an apparatus includes a bulk write circuit to generate a bulk write message to send to a destination agent to cause the destination agent to write data comprising register contents into a plurality of registers, at least some of the plurality of registers comprising non-consecutive registers. The bulk write message may include a first message header, a first chunk header including an address of a first register of a first subset of the plurality of registers, and a first payload portion having the register contents for the first subset of the plurality of registers. Other embodiments are described and claimed.