Calculating CPU Utilization with 5 Processes & 30% I/O Time

  • Thread starter zak100
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In summary: Inside the math.stackexchange post by "snr - Reinstate Monica" that @zak100 without attribution quoted, it's ##1-P^n## -- the google preview that he also quoted drops the superscript.
  • #1
zak100
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Mod note: Initially posted in a non-HW forum section, so missing the template
Summary::
Hi,
I am trying to find CPU utilization

What is the CPU utilization if there are 5 processes running at the same time, and on average the CPU spends 30% of its time waiting on I/O completion?

The formula is :
The formula for CPU utilization is 1−pn, in which n is number of process running in memory and p is the average percentage of time processes are waiting for I/O.

What is P in this formula?: 1-P ^n
I found a solution which finds the CPU utilization for each process separately.
Can we do it in the following way:
1- (0.3)^5
= 0.9975

Is the above answer correct?
Somebody please guide me. Zulfi.
 
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  • #2
It's not that simple. Performance management is its own whole discipline. Generally in a CPU set the IO processor(s) may be viewed as distinct from the MMU (memory management unit(s)) and from the ALU (arithmetic and logical unit(s)), but there's still communication between them, and you have to measure based on specific processes.
 
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  • #3
zak100 said:
Summary:: Hi,
I am trying to find CPU utilization

What is the CPU utilization if there are 5 processes running at the same time, and on average the CPU spends 30% of its time waiting on I/O completion?

The formula is :

The formula for CPU utilization is 1−pn, in which n is number of process running in memory and p is the average percentage of time processes are waiting for I/O.
What is P in this formula?: 1-P ^n
What is the formula you're working with? In what you quoted, it has ##1 - pn##. Just above you have ##1 - P^n##.
zak100 said:
I found a solution which finds the CPU utilization for each process separately.
Can we do it in the following way:
1- (0.3)^5
= 0.9975

Is the above answer correct?
Somebody please guide me. Zulfi.
You attached an image, but I am not able to view it.

Also, this is a homework question, so should be posted in the Eng. & Comp Sci Homework section. I am moving to that forum section, but in future homework questions, please post them in that section.
 
  • #4
Hi,
Please provide the link where you have moved the question.

Zulfi.
 
  • #5
zak100 said:
Please provide the link where you have moved the question.
Zulfi.
The link was there for 1 day, Apparently you figured out where to look for your moved post.

From my post last Thursday...
Mark44 said:
What is the formula you're working with? In what you quoted, it has ##1 - pn##. Just above you have ##1 - P^n##.
Mark44 said:
You attached an image, but I am not able to view it.
 
  • #6
Hi,
Okay I would know about the link, once I get any reply.

Zulfi.
 
  • #7
Enough about the link.

How about the questions I asked? It's not clear what you need to do, since you have two different formulas, and an uploaded image that was blank.
 
  • #8
Sorry, I don't have any clue for the image. I don't know who did that. I have to change my password. I don't use such numbers for images.

Hope you would now provide me the link.

Zulfi.
 
  • #9
zak100 said:
Sorry, I don't have any clue for the image. I don't know who did that. I have to change my password. I don't use such numbers for images.
The original post, which was moved by @berkeman, had an image link in it. I don't see that link any longer. Possibly the image was just the part that is quoted in post #1, that follows "The formula is:"
zak100 said:
Hope you would now provide me the link.
Let's forget about the image link.

For the third time...
Mark44 said:
What is the formula you're working with? In what you quoted, it has ##1 - pn##. Just above you have ##1 - P^n##.
Right now, this is all I'm concerned with.
Is the formula ##1 = pn## or is it ##1 - P^n##?
 
  • #10

1. How do you calculate CPU utilization with 5 processes?

To calculate CPU utilization with 5 processes, you need to divide the total time the CPU was busy by the total time. This will give you a percentage, which represents the CPU utilization.

2. What is the significance of 30% I/O time in calculating CPU utilization?

I/O time refers to the time the CPU spends waiting for input/output operations to be completed. In a system with multiple processes, a high I/O time can indicate that the CPU is spending a significant amount of time waiting for external devices, which can affect its overall utilization.

3. Can CPU utilization be higher than 100% with 5 processes and 30% I/O time?

No, CPU utilization cannot be higher than 100%. This value represents the maximum amount of time the CPU was busy during a given period. If the CPU is constantly busy with multiple processes and a high I/O time, it may indicate that the system is overloaded and may need to be optimized.

4. How does the number of processes affect CPU utilization?

The more processes running on a system, the higher the CPU utilization will be. This is because each process requires the CPU's attention and resources, resulting in a higher overall utilization. However, if the system is well-optimized and has enough processing power, it should be able to handle multiple processes without significantly impacting its performance.

5. What are some factors that can affect CPU utilization with 5 processes and 30% I/O time?

Some factors that can affect CPU utilization include the number and complexity of processes running, the efficiency of the operating system and hardware, and the amount of available processing power. Additionally, external factors such as network connectivity and input/output operations can also impact CPU utilization.

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