Non atomic RTT #699
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Non atomic RTT #699
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While it seems to work to replace |
TheButlah
reviewed
Oct 4, 2022
| @@ -13,13 +10,13 @@ pub(crate) struct Channel { | |||
| pub buffer: *mut u8, | |||
| pub size: usize, | |||
| /// Written by the target. | |||
| pub write: AtomicUsize, | |||
| pub write: critical_section::Mutex<RefCell<usize>>, | |||
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Is there a benefit to the mutex approach instead of using the atomic-polyfill crate from embassy?
If I understand correctly, that crate will use the native atomics when available, and polyfill atomics using critical-section when native ones aren't available
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That might indeed be the better option.
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This PR replaces all atomic variables with their non-atomic counterpart wrapped in a
critical_section::Mutex<RefCell<_>>. TheRefCellis needed, becausecritical_section::Mutexdoes not provide interior mutability.This change makes
defmt-rttavailable on targets without native atomics.Fixes #597.
Atm, it is unclear what the runtime and code-size impact of that change is. Likely both would improve if using a
Cell, instead of aRefCell, but it is unclear if that would be correct.