On Wed, Aug 27, 2003 at 11:22:54PM +0100, Alan Cox wrote: > Nod.. I'm trying to fathom the 3Mbyte/second behaviour while hdparm > claims DMA is on I thought each PIO READ costs something like 400 or 500 cycles on c3k (400Mhz CPU). 400/3 == 133 cycles/byte. Either doing very slow DMA or 32-bit (4*133 == 532) reads. Then it would make sense. grant