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iMX6 data cache prefetch

Question asked by ofer.livny on Jun 12, 2014
Latest reply on Jun 18, 2014 by igorpadykov

Hi

 

I noticed that the iMX6 cache prefetching is disabled, and then found the erratum on that topic, saying that enabling  prefeching can lead to deadlock or data corruption.

 

My questions are -

 

1. I want to enable prefetching, to see how often my application will suffer from this issue. How can I do that? (I'm using iMX6Q running u-boot 2009 and linux 3.0.35_4.1)

I found the ARM documentation regarding ACTLR register (ARM Information Center) but couldn't find the right place to update this value in the u-boot / kernel.

 

2. When doing some profiling on my DDR I see a big difference between reads and writes - DDR write is more  or less x8 faster than reads. Assuming that data prefetching is disabled - does this difference make sense?

The profiler is doing continuous block reading/writing for blocks larger than the L2 cache.

 

 

Thanks,

Ofer

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