Top command is executed, the results appear a bunch of do not know what it means, so look for a pass, probably thoroughly understand the meaning of the output, the more important of several parameters are:
US: the User State User state information
sy: system state information kernel mode
id: idle
user mode and kernel mode is Gesha, with a glance of FIG:
the cpu seemingly parallel processing task work is actually a serial task will be divided into a plurality of small fragments, each time only the kernel a fragment processing of a task, has been dealt a second segment will jump to the task, if the loop jump, because the processing time for each small segment is very short, in the end gives us the feeling that all tasks are processed simultaneously . Process task kernel is being processed kernel mode, this time a user submits a new request, called user mode, kernel will give priority to new requests submitted by the user.
