On Sun, Jul 18, 2004 at 10:30:16AM +0100, Hamie wrote:Well... I did consider that. And not to disbelieve you, since you know the kernel way better than I do, But decided I was being silly that a 1.6GHz Pentium-M processor should use 100% CPU moving a couple of MB/second across a CF interface...
Anyone know why this happens? Something busy waiting? (BUt that should show as system cpu right?) or something taking out really long locks?
It'll be because IDE is using PIO to access the CF card, which could
have long access times (so reading a block of sectors could take some
time _and_ use CPU.) Obviously, PIO requires the use of the CPU, so
the CPU can't be handed off to some other task while this is occuring.