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I'm working on optimizing a function which uses floating point instructions.

For bench marking I need to know execution latency of the instructions to know theoretical possible performance.

I have found such manual for A57: http://infocenter.arm.com/help/topic/com.arm.doc.uan0015b/Cortex_A57_Software_Optimization_Guide_external.pdf

But, I don't find any such doc for A53. Am I missing something? Is there any such optimization guide available for A53?

Vikram Dattu
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2 Answers2

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Some saint independently measured the instruction latencies.

http://hardwarebug.org/2014/05/15/cortex-a7-instruction-cycle-timings/

Note that the a53 evolved from the a7 and hence the timings are likely similar. It is a completely different design from the a57, which has a much longer pipeline and out of order execution.

user364952
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Unfortunately, to the best of my knowledge, there's very little information about the Cortex A53 cycle timings. Crucially, from my measurements, the NEON latencies are quite different from what's happening on the Cortex A7.

I've written microbenchmarking software to figure out what's going on with regards to the instruction cycle timings. There are some tables in the paper that was related to this work (also on IACR eprint).

Thom Wiggers
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