What is the most time consuming operation on the CPU?

Question

Programming

You need to simulate some kind of blocking operation. I think some kind of calculation in the loop would be a good option. Question. What is better to count so that the CPU works longer?

Answer 1

sleep(1000)

Answer 2

What is better to count so that the CPU works longer?

rep nop

Answer 3

Yes, anything, even an empty loop - the main thing is more iterations. And turn off the optimization options, otherwise the compiler can remove the cycle from the executable file.

Answer 4

a|1=a^a=a*a*a*a*a...=a+a+a+a+a...=a++;a++a;++a;a++;...
And then try to calculate 123546789|1

Answer 5

Time to interrupt the idle cycle.

Answer 6

all these mathematical operations in loops are very well optimized by the hardware itself, even if you disable optimization in the compiler.
so the most expensive operation is unpredictable, a conditional branch from random data is great for this, the processor will not be able to accurately predict this conditional branch.
well, blocking operations are emulated simply by slips.