CPU question??

Question

Consider a swapping system. Measured utilization are:
-CPU utilization 20%
-Swapping device (drum) 99.7%
-Other I/O devices 5%
What will be the effect on CPU utilization if we:
a.) get faster CPU
b.) get a bigger drum
c.) increase the degree of multiprogramming
d.) decrease the degree of multiprogramming
e.) get faster other I/O devices

Answer 1

If your swap device is essentially 100% busy, your system is memory bound, and your best strategy, although it is not among the 5 options you list, is to add more RAM (Random Access Memory), so that swapping out memory pages so much is not required. If you do that, swap utilization will fall, and CPU utilization should increase, as will (probably) other I/O utilization (if there is I/O to be done).



Generally, swapping does not contribute significantly to CPU loading on modern computer systems, which implement DMA (Direct Memory Access) in their memory controllers. Using DMA, memory "pages" are managed by the memory controller with little CPU involvment, except for the MMU (Memory Management Unit). This has been common in Intel chips since the later versions of the 486 line, in Motorola and PPC chips since the 68030, and in most other processor familes since the early 1990's.

Answer 2

Drum??? I don't know what you're talking about.

If you are overusing your swap space like in linux then you should just increase its size. You don't need a new CPU if it isn't broken.

Answer 3

b

Answer 4

the answer is b