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Jens Axboe wrote: > On Thu, Nov 17 2005, Pierre Ossman wrote: > >> Ok. Being a block device, the segments are usually rather large so the >> overhead of setting up many DMA transfers shouldn't be that terrible. >> > > The segments will typically be paged size, so could be worse. It all > depends on what your command overhead is like whether it hurts > performance a lot or not. > > MMC overhead is a lot larger than sending new addr/len tuples to the hardware. So I suppose there is performance to be gained by iterating over the segments inside the driver. Thanks for clearing things up. Maybe someone could update DMA-mapping.txt with the things you've explained to me here *hint* ;) Rgds Pierre - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ | ||||||||||
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