how to calculate CPU wait time?
from v$osstat we can find the records:
IDLE_TIME 237730525 1
BUSY_TIME 94953347 2
USER_TIME 53186839 3
SYS_TIME 41766508 4
IOWAIT_TIME 9644518 5
from the above we can see:
IDLE_TIME means CPU is doing nothing, BUSY_TIME means CPU is doing business, and I think it also includes the wait during the processing business. USER_TIME is the called from user level, SYS_TIME is the time called by system. and IO IOWAIT_TIME is the time CPU is waiting for IO.
it is more like BUSY_TIME=USER_TIME+SYS_TIME
the WAIT TIME I think it not only contains the IO wait time, but also include some other waits. then how to get the real WAIT time?