Comment by mwcampbell

3 years ago

> So calling another process can be used almost like a subroutine call.

Any numbers on the overhead of a message send/reply round trip compared to a subroutine call? I always assumed it was just axiomatic that the difference in latency between those two options would be orders of magnitude.

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mwcampbell

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jeffreygoesto  3 years ago

I don't have numbers, but the key ingredient is really minimizing context switches. This also results in priority inheritance while message passing which means that a high priority process gets the answer with it's own high priority, even if sending a message to a low priority process. Very smart.

Teading the old open sourced sources can be quite interesting...

https://github.com/vocho/openqnx/tree/master/trunk/lib/qnx43...