cleanup: restrict broadcast channels to the output component#557
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cleanup: restrict broadcast channels to the output component#557
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This is a small cleanup regarding the usage of broadcast channels. Currently the RateLimiter implementation is using this type of channel to receive events from HostScanner and forward them to the output component. Since there are not other tasks involved, a mpsc channel can be used without wrapping the event being passed in an Arc, this should somewhat reduce contention since the Arc will not have its reference changed when passing between components. More importantly, we have discussed in the past moving most of the code away from tokio and use regular threads instead, since our workload is CPU bound, the std library does not have a broadcast channel but it does have mpsc, so this should make the change easier in the future. Finally, this makes it clear the flow of events is linear and only diverges when multiple outputs need to be used in parallel.
5 tasks
Stringy
approved these changes
Apr 27, 2026
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Description
This is a small cleanup regarding the usage of broadcast channels.
Currently the RateLimiter implementation is using this type of channel to receive events from HostScanner and forward them to the output component. Since there are not other tasks involved, a mpsc channel can be used without wrapping the event being passed in an Arc, this should somewhat reduce contention since the Arc will not have its reference changed when passing between components. More importantly, we have discussed in the past moving most of the code away from tokio and use regular threads instead, since our workload is CPU bound, the std library does not have a broadcast channel but it does have mpsc, so this should make the change easier in the future.
Finally, this makes it clear the flow of events is linear and only diverges when multiple outputs need to be used in parallel.
Checklist
Automated testing
If any of these don't apply, please comment below.
Testing Performed
CI should be enough, behavior should not be modified.