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The higher load, the lower idle?Is there a situation that high load meanwhile high idle out there?

a screen shot

fixer1234
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SpawnST
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  • The very meaning of “load” (dictionary-wise) tells you it can never mean idle. I highly recommend you read the Wikipedia article on [Load (as in computing)](https://en.wikipedia.org/wiki/Load_(computing)). – Daniel B Mar 03 '17 at 14:29
  • @Daniel i know they're different.What i suspect is they're related. – SpawnST Mar 03 '17 at 14:33
  • Of course they’re related. They have opposing meanings. However, they measure different things, so they cannot be compared directly. – Daniel B Mar 03 '17 at 14:43
  • On macOS I can say for a fact that you can have high load (a lot more than 1 per core) and have fairly high cpu idle (>50%) at the same time. Seems very strange to me, but it can definitely happen. – Klas Mellbourn Jun 02 '20 at 15:41

2 Answers2

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The two are directly related. Load% + Idle% = 100%.

That means when one increases, the other decreases. No exceptions.

Imagine a glass with water. The water + the remaining empty space totals the glass capacity. You cannot have more than 50% water and more than 50% free space in the glass at the same time.

Overmind
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  • From the Wikipedia I noticed that load and idle measure different things.how to explain idle +load=100? – SpawnST Mar 03 '17 at 11:09
  • The 2 things are part of the same integer and directly related, just like in the glass example. Idle time actually measures unused CPU capacity, while load shows the used one. – Overmind Mar 03 '17 at 11:29
  • I've updated a screen shot to specify the question.If they are directly related ,does it mean one can be caculated out according to another one's value?But I cannot see that.Thanks for ur time! – SpawnST Mar 03 '17 at 14:01
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From the Wikipedia load page you can see they are related, because:

For single-CPU systems that are CPU bound, one can think of load average as a percentage of system utilization during the respective time period. For systems with multiple CPUs, one must divide the number by the number of processors in order to get a comparable percentage.

And the lengthier explanation about load tells you that:

For example, one can interpret a load average of "1.73 0.60 7.98" on a single-CPU system as:

  • during the last minute, the system was overloaded by 73% on average (1.73 runnable processes, so that 0.73 processes had to wait for a
    turn for a single CPU system on average).

  • during the last 5 minutes, the CPU was idling 40% of the time on average.

  • during the last 15 minutes, the system was overloaded 698% on average (7.98 runnable processes, so that 6.98 processes had to wait
    for a turn for a single CPU system on average).

This will tell you that the load will point out the processor time necessary to execute all the waiting processes, thus, the higher the load the less idle time you will have until that load reaches 0.

fernando.reyes
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