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A lot of realtime systems don’t have sufficient resources to run Linux. Their hardware is much less powerful than Linux requires. Even if a system can run (RT-
by lumb63 3y ago
A lot of realtime systems don’t have sufficient resources to run Linux. Their hardware is much less powerful than Linux requires.
Even if a system can run (RT-)Linux, it doesn’t mean it’s suitable for real-time. Hardware for real-time projects needs much lower interrupt latency than a lot of hardware provides. Preemption isn’t the only thing necessary to support real-time requirements.
- skyde 3y agowhat kind of Hardware is considered to have "lower interrupt latency"? Is there some kind of Arduino board I could get that fit those lower interrupt latency required for real-time but still support things like Bluetooth?
- lumb63 3y agoTake a look at the Cortex R series. The Cortex M series still has lower interrupt latency than the A series, but lower processing power. I imagine for something like Bluetooth that an M is more than sufficient.
- refulgentis 3y agoSure but that was already mentioned before the comment I was replying to. Standard hardware not being great for realtime has nothing to do with hypothetical realtime Linux.
- rcxdude 3y agorealtime just means execution time is bounded. It doesn't necessarily mean the latency is low. Though, in this sense RT-linux should probably be mostly thought of as low-latency linux, and the improvement in realtime guarantees is mostly in reducing the amount of things that can cause you to miss a deadline as opposed to allowing you to guarantee any particular deadline, even a long one.