On 08/04/2010 12:34 PM, Pawel Osciak wrote:
Richard Röjfors<richard.rojfors@xxxxxxxxxxxxxx> wrote:
On 08/04/2010 11:50 AM, Pawel Osciak wrote:
How do you propose to allocate the buffers? They need to be contiguous
and using uncached memory gave really bad performance.
829440 bytes is a quite a lot and one can't reliably depend on kmalloc
to be able to allocate such big chunks of contiguous memory. Were you
testing this on a freshly rebooted system?
The systems have been running for a while, but not days.
I don't see why would dma_alloc_coherent work better than kmalloc?
In principle it wouldn't. It's just it's much less intensively used and
allocates from a special area. Not really a bullet-proof solution either
though, I agree.
So what is your proposal given the current situation?
Using dma_alloc_noncoherent instead of kmalloc and use dma_cache_sync
instead of dma_sync_single_for_cpu?
--Richard
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