So I would assume that delay_tsc() probably only makes the situation worse for the libata tests, but the real problem is at __switch_to() and schedule(). Do you agree with these assumptions?Yes. I agree that percentage of CPU time is unreasonably high for these functions. But not only for them.
Is there a way to for oprofile to report the time spent in function calls depending on the call trace?I don't know any.
Thanks again for the help. I guess if that doesn't lead anywhere I'll just start compiling older vanilla kernels and see when the problem dissapears. But this needs a lot of time and I'm not sure for how long I'll be able to not offer any service with those disks (I was supposed to use RAID 0 to provide storage space with them, but with the current problems that wouldn't be so wise).Probably this is the best and fastest way to diagnose problem.
DimitrisRegards
http://link.interia.pl/f1b41