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If they are talking about jitter they should call it jitter. Noise is something completely different. The RT folks will just shake their heads.
by rurban 4y ago
If they are talking about jitter they should call it jitter. Noise is something completely different. The RT folks will just shake their heads.
- 2OEH8eoCRo0 4y agoJitter deals with signals. At this level we are not dealing with signals but operating system tasks.
- rurban 4y agoThe main cause of jitter are of course external interrupts, bad hardware or drivers. The main task of the OS is to provide drivers which do not block too long. Internal kernel book-keeping tasks of course also, but the main point of OS tasks are driver requests, interrupting system tasks. Calling it noise is just strange. Noise is usually the rand() source.
- mlyle 4y agoJitter and phase noise are closely related. Here the units are a bit weird, but we're talking about accumulated noise. Systems seek to reach 0. This really means "no variability in performance", not just "tasks start at the right time". Performance noise is the correct term for what's measured. See e.g. https://www.researchgate.net/publication/353781546_Influence_of_Noisy_Environments_on_Behavior_of_HPC_Applications https://www.researchgate.net/publication/353781546_Influence... for a discussion.