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In the name of Godthe Most Compassionate

the Most Merciful

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Embeded systems Future architectureMohammad Amin Khorsandi

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What are embedded systems?

1- Low power2- Fast (critical throughput) 3- Particular task4- Reliable5- Cheap6- Small size

Applications:

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Platforms:

Microcontrollers Microprocessors FPGA Digital signal processors Application specific integrated circuits

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Power consumption reduction

Power is influenced by voltage andpulses on each part of hardware

Traditional idea:Reducing voltage and frequency if necessary

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Power consumption reduction

New ideareducing hardware to obtain the least states between instructions, data and functional units.

Instruction>>Pipeline, branch prediction, memory access, speculation and etc.>>function unit

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Fast? How come? How much?

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worst-case of execution time

Pipeline (hazards and stages)SpeculationeventsBranch miss predictionCache miss

Computing maximum band of execution time:Exclude as many possible timing accident

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Shorter instructions

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Cache

The most important consideration for cache speedup is predictability.

May: upper approximations of cache contentMust: lower approximations of cache contentEvict: when “may” information becomes availableFill: when “must” and “may” information is obtained

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Predictability of k-way LRU/PLRU/FIFO

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Multicores

Not highly recommended Avoiding shared resources conflict Using crossbars for communication

between shared resources Private L1 and L2 replacement

strategies

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Conclusion

Simplifying the hardware causes increasing in critical throughput and power saving

We must take care of these simplicities

Software must carry the burden of simplicity in hardware.