kmalloc memory slower than malloc

[Thommy Jakobsson]

On Tue, 10 Sep 2013, Duan Fugang-B38611 wrote:

> About the diff:
> dma_alloc_coherent in kernel   4.256s (s=0)
> dma_alloc_coherent userspace   0.566s (s=0)
> 
> I think it call remap_pfn_range() with page attribute (vma->vm_page_prot) transferred from mmap() maybe cacheable.
> So the performance is the same as malloc/kmalloc in userspace.
> 
Thats probably true, or at least that is how I explained it to myself in 
my head =) 

Thanks,
Thommy