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Why performance is higher on LITTLE cores?

Hi all,

I am using the HiKey970 board to run inferences on neural networks. The board comprises ARM Cortex-A73 and ARM Cortex-A53 cores.
I am using `taskset` to pin the inference process (that spawns 4 threads) once on the LITTLE cores (0-3) and once on the big cores (4-7). Contrary to what I was expecting, the inference time is almost double when running on big cores, compared to LITTLE cores.

Is there an explanation for this behavior? Are there tools that can help me understand why the threads are slower when using big cores?

To be more precise, the board is flashed with kernel version 4.9.78-147538-g244928755bbe, the code that I am using can be found in this repo.

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  • Hi ,

    thank you for the suggestion. The specific distribution does not provide trans_table, but I monitored 

    /sys/devices/system/cpu/cpufreq/policy4/stats/total_trans
    .

    For the big cores I didn't see any increase in the transitions after running inference.

    I think the performance issue is caused by a different source.

Reply
  • Hi ,

    thank you for the suggestion. The specific distribution does not provide trans_table, but I monitored 

    /sys/devices/system/cpu/cpufreq/policy4/stats/total_trans
    .

    For the big cores I didn't see any increase in the transitions after running inference.

    I think the performance issue is caused by a different source.

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