Re: simple framebuffer slower by factor of 20, on socfpga (arm) platform

[Tomi Valkeinen]

On 24/04/15 16:29, Pavel Machek wrote:
> Hi!
> 
> On Fri 2015-04-10 12:35:52, Archit Taneja wrote:
>>> That said, if the fb is in RAM, and is only written by the CPU, I think
>>> a normal memcpy() for fb_memcpy_fromfb() should be fine...
>>
>> I didn't test for performance regressions when I posted this patch.
>>
>> A look at _memcpy_fromio in arch/arm/kernel/io.c shows that readb() is used
>> all the time, even when the source and destination addresses are aligned for
>> larger reads to be possible. Other archs seem to use readl() or readq() when
>> they can. Maybe that makes memcpy_fromio slower than the implementation of
>> memcpy on arm?
> 
> Ok, can you prepare a patch for me to try? Or should we just revert
> the original commit?

The old way worked fine, afaik, so maybe we can revert. But still, isn't
it more correct to use memcpy_fromio? It's (possibly) io memory we have
here.

 Tomi

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