MESSAGE
| DATE | 2015-04-27 |
| FROM | Ruben Safir
|
| SUBJECT | Subject: [LIU Comp Sci] Fwd: OS Cpt 9 27 question
|
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Subject: [LIU Comp Sci] Fwd: OS Cpt 9 27 question
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-------- Forwarded Message --------
Subject: OS Cpt 9 27 question
Date: Mon, 27 Apr 2015 20:57:24 -0400
From: Ruben Safir
To: Mohammed Ghriga , oshw <643-at-ghriga.com>
9.27
Consider a demand-paging system with the following time-measured
utilizations:
CPU utilization 20%
Paging disk 97.7
Other I/O devices 5%
For each of the following, indicate whether it will (or is likely to)
improve
CPU utilization. Explain your answers.
a. Install a faster CPU.
not really although the CPU is being taxed
b. Install a bigger paging disk.
What, and Page MORE??
c. Increase the degree of multiprogramming.
No - they will cause more page faults.
d. Decrease the degree of multiprogramming.
Not really , uness you can't do other things
e. Install more main memory.
YES YES
f. Install a faster hard disk or multiple controllers with multiple hard
disks.
Maybe - since you are paging your disk drive so heavy, but you need to
get those pages out of swap
g. Add prepaging to the page-fetch algorithms.
can help
h. Increase the page size.
Yes after you add more ram.
This question is a problem. 20% on the CPU is HUGE on any system I've
sat on in 15 years. For example my server is currently stats like this
ruben-at-www:~> lscpu
Architecture: i686
CPU op-mode(s): 32-bit
Byte Order: Little Endian
CPU(s): 1
On-line CPU(s) list: 0
Thread(s) per core: 1
Core(s) per socket: 1
Socket(s): 1
Vendor ID: GenuineIntel
CPU family: 6
Model: 28
Stepping: 2
CPU MHz: 1097.324
BogoMIPS: 2194.64
L1d cache: 24K
L1i cache: 32K
L2 cache: 512K
ruben-at-www:~> vmstat -s
1019632 K total memory
731612 K used memory
213504 K active memory
438760 K inactive memory
288020 K free memory
12920 K buffer memory
375384 K swap cache
2103292 K total swap
134700 K used swap
1968592 K free swap
510930761 non-nice user cpu ticks
624699 nice user cpu ticks
28583604 system cpu ticks
892583294 idle cpu ticks
17188197 IO-wait cpu ticks
16057 IRQ cpu ticks
8281524 softirq cpu ticks
0 stolen cpu ticks
114657493 pages paged in
725614587 pages paged out
1530727 pages swapped in
2845266 pages swapped out
2629837040 interrupts
572576841 CPU context switches
1415499250 boot time
6822977 forks
top - 20:43:50 up 169 days, 22:29, 5 users, load average: 0.84, 0.81, 0.79
Threads: 204 total, 1 running, 203 sleeping, 0 stopped, 0 zombie
%Cpu(s): 0.7 us, 0.3 sy, 0.0 ni, 99.0 id, 0.0 wa, 0.0 hi, 0.0 si,
0.0 st
KiB Mem: 1019632 total, 734580 used, 285052 free, 12944 buffers
KiB Swap: 2103292 total, 134700 used, 1968592 free, 377532 cached
Yes that is a 0.7 CPU
My workstation using a dual Intel Core?
top - 20:52:18 up 1 day, 48 min, 6 users, load average: 0.36, 0.22, 0.16
Tasks: 144 total, 1 running, 143 sleeping, 0 stopped, 0 zombie
%Cpu0 : 11.4/1.3 13[|||||||
]
%Cpu1 : 8.8/0.7 9[|||||
]
GiB Mem : 88.8/3.189 [
]
GiB Swap: 0.0/0.000 [
]
11% while it is playing a dvd.
SO - there is a lot wrong with this system
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