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0 pointsxwolfi3y ago0 comments

What should I say, trying to go sub millisecond, one profiling run at a time, sigh...

0 comments

Sub millisecond timing is basically impossible with context switching involved. Even on a real time kernel config, the best you are going to get with a time slice is 1ms.

With busy waiting, you can achieve timings in the sub-microsecond range, depending on how heavy the loop is.

bitcharmer3y ago

Not sure what you mean by that but nanosecond precise timing across cpu cores have been reliable for quite a while now.

Key words: constant TSC, invariant TSC, TSC clocksource

tsegratis3y ago

The hardware providing those nanoseconds is not nanosecond accurate (unless using atomic clock)

However they may be more accurate than 1ms. The guy is saying the timeslice given by the OS for a program to run in has at best a 1ms slot because the OS is switching between threads on a 1ms timeslice basis

So unless you're polling, the timing at which you ask the hardware for nanoseconds will jitter with 1ms offsets

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