Processor Performance Monitoring Circuitry With Fixed TMA Counters
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Solution Overview
Problem
Current performance monitoring mechanisms in processors lack precision and efficiency in gathering and differentiating top-down microarchitecture analysis (TMA) data due to limited programmable counters, leading to inconsistent and time-consuming data collection.
Innovation Solution
Implementing a set of fixed counters for high-level performance metrics in processors, reducing the need for multiplexing and providing precise, fast access to TMA data, while offloading programmable counters for lower-level events.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If multiplexing is used to gather TMA data with limited programmable counters, then device complexity is reduced, but measurement precision deteriorates and data collection becomes inconsistent
Solution Approach 1:
The patent segments the counter resources into two distinct types: fixed counters dedicated to TMA metrics and programmable counters for other events. This segmentation eliminates the need to multiplex limited programmable counters for TMA data collection, thereby maintaining high measurement precision while keeping the overall system manageable through clear functional separation.
Solution Approach 2:
The patent introduces fixed counters as an intermediary resource specifically for TMA metric collection. These fixed counters act as a dedicated buffer between the performance monitoring needs and the main programmable counter system, preventing multiplexing conflicts and ensuring consistent, precise data collection without burdening the programmable counters.
2Device complexity
If multiplexing is used for performance monitoring, then device complexity is reduced, but data collection time increases
Solution Approach 1:
By segmenting counter functions into fixed and programmable categories, the patent enables parallel operation where fixed counters continuously collect TMA data without being switched in and out like multiplexed counters. This eliminates the time loss associated with multiplexing while maintaining manageable system complexity through clear functional division.
Solution Approach 2:
The fixed counters are pre-configured and dedicated to specific TMA metrics before runtime, eliminating the need for dynamic configuration changes during data collection. This preliminary setup ensures that TMA data can be collected continuously and efficiently without the time penalties of multiplexing operations.
3Measurement precision
If fixed counters are implemented for TMA metrics, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent extracts the TMA metric collection function from the general-purpose programmable counters and places it in dedicated fixed counters. This extraction improves measurement precision by eliminating multiplexing interference while managing complexity through functional separation—the fixed counters handle only TMA metrics, keeping their configuration simple and predictable.
Solution Approach 2:
The programmable counters retain their universal, multi-functional capability to handle various non-TMA events, while the fixed counters specialize in TMA metrics. This division allows the programmable counters to remain versatile resources while the fixed counters provide dedicated precision for TMA data, balancing overall system complexity with improved measurement capability.
Data Source
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AI summary
Techniques for performance monitoring are described. In certain examples, an apparatus (e.g., a processor) includes a first set of execution circuits of a first type; a second set of execution circuits of a second type different than the first type; an allocation circuit to allocate a first set of one or more ports for the first set of execution circuits of the first type, and a second set of one or more ports for the second set of execution circuits of the second type; and a performance monitor circuit to generate a first value that indicates a first number of ports of the first set of one or more ports that delayed pushing out a ready to execute micro-operation of the first type to the first set of execution circuits of the first type due to being busy executing another micro-operation of the first type, and a second value that indicates a second number of ports of the second set of one or more ports that delayed pushing out a ready to execute micro-operation of the second type to the second set of execution circuits of the second type due to being busy executing another micro-operation of the second type.