Hello,
We have a custom board where we reserve memory outside Linux memory space to be used for video buffers. Access to this memory seems to be at least 10 times slower than accessing other memory. For example a memcpy from 1 application to another application tasks 10 ms, while a memory copy from this video memory tasks 125 ms. The though is that the data cache is not enabled correctly. So some questions:
Are there any tools/methods to see the cache configuration for different memory sections?
Where in Linux is the cache configured for the AM3157 processor?
Any other thoughts on what could be causing the slow memory access to this memory that is defined outside of user space?
Also: We saw this same slow memory issue when we where using V4L and having the kernel allocate the buffers. I believe this is using the constant DMA memory.
Regards,
Craig