My last systems programming class was already a few years ago and I am a bit rusty, so I got some questions:
1. Looking at the code in https://github.com/elast0ny/raw_sync-rs/blob/master/src/even...) it looks like we are using a userspace spinlock. Aren't these really bad because the mess with the process scheduler and might unnecessarily trigger the scaling governor to increase the cpu frequency? I think at least on linux one could use a semaphore to inform the consumer that new data has been produced.
2. What kind of memory guarantees do we have on modern computer architectures such as x86-64 and ARM? If the producers does two writes (I imagine first the data and then the release of the lock) - is it guaranteed that when the consumer reads the second value that also the first value has been synchronized?
My last systems programming class was already a few years ago and I am a bit rusty, so I got some questions:
1. Looking at the code in https://github.com/elast0ny/raw_sync-rs/blob/master/src/even...) it looks like we are using a userspace spinlock. Aren't these really bad because the mess with the process scheduler and might unnecessarily trigger the scaling governor to increase the cpu frequency? I think at least on linux one could use a semaphore to inform the consumer that new data has been produced.
2. What kind of memory guarantees do we have on modern computer architectures such as x86-64 and ARM? If the producers does two writes (I imagine first the data and then the release of the lock) - is it guaranteed that when the consumer reads the second value that also the first value has been synchronized?