On Wed, Oct 30, 2002 at 09:36:59AM -0000, James Stevenson wrote: > > Quoting James Stevenson <james@stev.org>: > > > > > > > > alot depends greatly on the hardware and how much data > > > has to be transfered. > > > > > > > > But quite often if DMA fails for some reson it will > > > try to fall back to PIO something working slowly > > > can be better than not working at all. > > Is it always useful (even for the small data transfer) to use DMA ? > > for small transfere it can have the same over head to set up > the dma transfere as it does to transfere the data in a case > like this there it no point in using DMA But remember disks are always accessed in terms of blocks and they are 512 bytes. Thus the question stands, is DMA setup faster than sending 512 bytes to the bus? ------------------------------------------------------------------------------- Jan 'Bulb' Hudec <bulb@ucw.cz> -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ FAQ: http://kernelnewbies.org/faq/
