Memory Traffic Priority Based on Image Sensor Metadata
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Solution Overview
Problem
Current memory traffic prioritization methods in systems with image sensors often lead to performance issues like frame stuttering and increased power consumption due to inadequate prioritization of memory access, particularly when using bad priority indicators, and require complex retuning for different camera sensors.
Innovation Solution
The system employs image sensor protocol metadata to prioritize memory traffic by identifying and utilizing metadata from both the image sensor physical and link layers, such as power state mode data and packetization information, to dynamically adjust memory access priorities across various arbitration schemes, including round robin, weight, deadline, and buffer occupancy schemes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a bad priority indicator of memory traffic is used to arbitrate memory access among clients, then memory access arbitration is simplified, but clients are starved of memory bandwidth and performance issues such as frame stuttering occur
Solution Approach 1:
The patent implements dynamic priority adjustment for memory traffic based on real-time conditions. The memory interface dynamically changes priority levels for different clients (image sensor, display, processor) depending on buffer occupancy, traffic patterns, and operational states, rather than using fixed priority indicators. This resolves the contradiction by maintaining simple arbitration logic while adapting priorities dynamically to prevent client starvation and performance issues.
Solution Approach 2:
The system uses feedback mechanisms to monitor memory buffer occupancy, traffic patterns, and client performance metrics. Based on this feedback, the memory interface adjusts priority indicators in real-time. For example, when the image sensor buffer is nearly full, the system increases priority for image sensor traffic; when display buffers are filling, it increases display priority. This feedback loop prevents starvation while maintaining simple arbitration.
2Speed
If DRAM is forced into unnecessarily high power states to handle high priority traffic, then memory access speed is improved, but power consumption increases
Solution Approach 1:
The patent implements dynamic power state management for DRAM based on actual traffic priorities and buffer conditions. Rather than maintaining DRAM in high-power states continuously, the system transitions DRAM between power states (active, self-refresh, power-down) based on real-time priority indicators and traffic patterns. This ensures fast access when needed while saving power during low-activity periods.
Solution Approach 2:
The system changes operational parameters of DRAM dynamically, specifically adjusting power state transitions based on priority traffic patterns. When high-priority traffic is detected (e.g., image sensor data during active capture), DRAM is kept in active high-speed states. When traffic priority decreases or buffers are full, DRAM transitions to lower power states like self-refresh or power-down, reducing consumption while maintaining accessibility.
3Reliability
If a larger on-chip buffer is implemented to mitigate the impact of bad priority indicators, then memory access stability is improved, but silicon area and cost increase
Solution Approach 1:
The patent implements dynamic buffer management where the system adjusts buffer occupancy thresholds and priority assignments based on real-time conditions rather than relying on oversized static buffers. The memory interface monitors buffer levels and dynamically adjusts priority indicators to prevent starvation, allowing smaller buffers to maintain stability through active management rather than passive size increase.
Solution Approach 2:
The system employs self-regulating mechanisms where the memory interface automatically adjusts priority indicators based on buffer occupancy levels without external intervention. When buffers approach capacity, the system autonomously increases priority for that client to ensure timely data transfer, preventing overflow and maintaining stability with minimal buffer size.
4Ease of operation
If weighing based on traffic pattern estimation is used to address unnecessary restriction of access to shared memory, then memory access fairness is improved, but labor and time intensity increases
Solution Approach 1:
The patent implements self-service priority adjustment where the memory interface automatically monitors traffic patterns and adjusts priority indicators without external configuration or manual tuning. The system autonomously detects traffic patterns (bursty, steady, intermittent) and adapts priority assignments accordingly, eliminating the need for labor-intensive manual estimation while maintaining fair shared memory access.
Solution Approach 2:
The system uses real-time feedback from memory traffic monitoring to automatically adjust priority weights. By continuously observing actual traffic patterns and buffer occupancy, the memory interface dynamically weighs access priorities to ensure fairness among multiple clients sharing memory bandwidth, replacing complex manual traffic pattern estimation with automated feedback-driven adjustment.
Data Source
AI summary
Systems, apparatuses, and/or methods may define a priority of image memory traffic based on image sensor protocol metadata. For example, a metadata identifier may identify image sensor protocol metadata corresponding to an image sensor physical layer and/or an image sensor link layer. Moreover, a prioritizer may define a priority of the image memory traffic based on the image sensor protocol metadata. The priority may be used to control client access to dedicated memory and/or to shared memory.