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I have a value that at 40 -> 80%, I want to reduce 80% to 50% and compute x such that x -> 50% would simple ration do this? Note percentage here is CPU usage and I want to increase resource from 40 to some value so that CPU usage can come down from 80% to 50%. Is my reasoning correct here?

    40  -> 80%
X + 40  -> 50%

I want to increase 40 to some value so that percentage is reduced to 50%.I did simple ratio which gives me 25, would adding 25 to 40 the right approach here?

user_1357
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1 Answers1

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Assuming that the flow of data to be processed is constant, we have that

  • $\#40$ corresponds to an utilization rate of $\to 80 \%$

which means that

  • $\#32$ corresponds to an utilization rate of $\to 100 \%$

and more in general

  • $\#N$ corresponds to an utilization rate of $\to P \%$ such that $N\cdot P=3200$

then we are looking for an utilization rate of $\to 50 \%$ that is

$$N\cdot 50=3200 \implies N=64$$

therefore we need to increase of $x=24$.

user
  • 154,566
  • I have a question on above. What is the whole quantity and why did we do (x+50) * 50%? Also not understanding reducing 40 to 10 and 50 to 20. I'm still not sure how much to increase 40 by. – user_1357 Oct 27 '20 at 16:25
  • @datauser If we claim that 40 is the 80% this mean that the whole quantity is 50? Am I right o are you considering something different? – user Oct 27 '20 at 16:27
  • To clarify, when you say whole quantity are you referring to if 80% of x = 40? where x = 50? How did you get 50? – user_1357 Oct 27 '20 at 16:46
  • @datauser Because 80% of 50 = 40. I've interpreted the given in this way. Isn't it correct? – user Oct 27 '20 at 16:49
  • Multiplied 50% with (x + 50) to keep the same ratio since whole quantity gives us at 100%? Could you elaborate reasoning there? Thanks – user_1357 Oct 27 '20 at 16:53
  • @datauser If we add a quantity x to 40 the same quantity is applied to the whole 50 and we need that 50%(x+50)=x+40 if I've interpreted properly your problem. – user Oct 27 '20 at 16:55
  • @datauser If the whole quantity is fixed to 50 then we simpli need to subtract 15 from 40 to obtain 25=50% of 50. – user Oct 27 '20 at 16:56
  • Hmm, I am still a bit confused. I am looking to increase 40 by something. If 50% of 50 is 25, can I increase 40 by 25? – user_1357 Oct 27 '20 at 17:01
  • @datauser Firstly, I would like to understand better what you mean by "I have a value that at $40 -> 80$%". Do you mean that the 80% of a certain quantity is equal to 40? – user Oct 27 '20 at 17:05
  • Sorry for the confusion. When I say 40 --> 80 I mean 40 CPUs causes 80% CPU utilization. I want to reduce CPU utilization to 50% typically this is done by adding more CPUs so I need to increase 40 by some value to reduce 80% CPU utilization to 50% – user_1357 Oct 27 '20 at 17:12
  • @datauser Ah ok, then I need to revisit that! – user Oct 27 '20 at 17:13
  • In terms of creating a ration, we need to increase cpus:40 by x to get percentage down to 50% given we know 40 cpus gives us 80% utilization. Would ratio I put up in original question correct? I need to know a number to increase 40 by. – user_1357 Oct 27 '20 at 17:16
  • @datauser We need to make some kind of assumption. Here I'm assuming that the flow of data to be processed is constant and then we have a flux of 3200, therefore to reduce the utilization rate at 50% we need 24 CPUs more. – user Oct 27 '20 at 17:23
  • that seems more correct, how did you get #32 -> 100%? – user_1357 Oct 27 '20 at 17:25
  • @datauser Assuming the flux constant we have that $4080=32100$. We need some kind of assumption to find a solution. Let me know if it can be useful. – user Oct 27 '20 at 17:26
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    Reasoning seems right. Thank you for all the help! – user_1357 Oct 27 '20 at 17:37