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Async/await waker support. #394

Merged
merged 1 commit into from
Dec 27, 2020
Merged

Async/await waker support. #394

merged 1 commit into from
Dec 27, 2020

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Dirbaio
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@Dirbaio Dirbaio commented Dec 26, 2020 •
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This adds register_recv_waker and register_send_waker methods to all socket types.

This is the minimum required changes to smoltcp to support being used in async/await code. This opens the door for higher-level crates that expose wrappers implementing async traits like AsyncRead/AsyncWrite, Future, Stream...

I believe this is the best way to go, because:

  • It is not clear which traits should smoltcp implement:
    • The std ecosystem has multiple competing incompatible traits, mainly tokio and futures.
    • The no_std ecosystem hasn't converged on any standard io traits yet. The tokio and futures traits aren't no_std compatible.
  • There are non-trivial tradeoffs when implementing async support: how are sockets allocated, is there a single global tcp/ip stack or multiple, how are lifetimes handled.

By delegating these choices to external crates, smoltcp can stay un-opinionated.

There's an example of using this to implement AsyncBufRead and AsyncWrite in embassy here. Wrappers for the tokio or futures traits would look very similar. The use of unsafe there is not necessary in theory, AsyncRead and AsyncWrite can be implemented in 100% safe Rust. AsyncBufRead probably will require unsafe in most cases, unfortunately.

Previously discussed on #382 and #267 .

whitequark
whitequark reviewed Dec 27, 2020
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LGTM other than inline comments. Nice work!

src/socket/waker_store.rs Outdated Show resolved Hide resolved
@Dirbaio Dirbaio merged commit 73bb62a into master Dec 27, 2020
@Dirbaio Dirbaio deleted the async branch December 27, 2020 16:33
@Dirbaio Dirbaio mentioned this pull request Jan 6, 2021
Closed
@sassman sassman mentioned this pull request Feb 15, 2021
Open
stlankes added a commit to stlankes/hermit-rs that referenced this pull request Mar 22, 2021
@stlankes
revise network integration and add support of futures
57f39bd 
smoltcp 0.7 provides async/await waker support (smoltcp-rs/smoltcp#394).
I followed the example implementation https://github.com/embassy-rs/embassy/tree/net/embassy-net
to add waker support in hermit-sys.

However, hermit-sys can be used in a multi-threaded applications.
Consequently, the implementation must be thread safed. In addition,
we still have an "network thread", which is wakeup by an interrupt.
The thread wakeups all waiting future. If no future is available,
the thread calls directly the IP stack.
@stlankes stlankes mentioned this pull request Mar 22, 2021
Merged
stlankes added a commit to stlankes/hermit-rs that referenced this pull request Mar 30, 2021
@stlankes
revise network integration and add support of futures
898e809 
smoltcp 0.7 provides async/await waker support (smoltcp-rs/smoltcp#394).
I followed the example implementation https://github.com/embassy-rs/embassy/tree/net/embassy-net
to add waker support in hermit-sys.

However, hermit-sys can be used in a multi-threaded applications.
Consequently, the implementation must be thread safed. In addition,
we still have an "network thread", which is wakeup by an interrupt.
The thread wakeups all waiting future. If no future is available,
the thread calls directly the IP stack.
@Charles-Schleich
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Looks like the AsyncBufRead and AsyncWrite example for embassy mentioned earlier has been moved here.
For those having trouble finding it.

stlankes added a commit to stlankes/hermit-rs that referenced this pull request Jun 25, 2021
@stlankes
revise network integration and add support of futures
76b98c3 
smoltcp 0.7 provides async/await waker support (smoltcp-rs/smoltcp#394).
I followed the example implementation https://github.com/embassy-rs/embassy/tree/net/embassy-net
to add waker support in hermit-sys.

However, hermit-sys can be used in a multi-threaded applications.
Consequently, the implementation must be thread safed. In addition,
we still have an "network thread", which is wakeup by an interrupt.
The thread wakeups all waiting future. If no future is available,
the thread calls directly the IP stack.
mkroening pushed a commit to mkroening/rusty-hermit that referenced this pull request Jun 29, 2021
@stlankes @mkroening
revise network integration and add support of futures
e9710f6 
smoltcp 0.7 provides async/await waker support (smoltcp-rs/smoltcp#394).
I followed the example implementation https://github.com/embassy-rs/embassy/tree/net/embassy-net
to add waker support in hermit-sys.

However, hermit-sys can be used in a multi-threaded applications.
Consequently, the implementation must be thread safed. In addition,
we still have an "network thread", which is wakeup by an interrupt.
The thread wakeups all waiting future. If no future is available,
the thread calls directly the IP stack.
stlankes added a commit to stlankes/hermit-rs that referenced this pull request Aug 2, 2021
@stlankes
revise network integration and add support of futures
6a7105f 
smoltcp 0.7 provides async/await waker support (smoltcp-rs/smoltcp#394).
I followed the example implementation https://github.com/embassy-rs/embassy/tree/net/embassy-net
to add waker support in hermit-sys.

However, hermit-sys can be used in a multi-threaded applications.
Consequently, the implementation must be thread safed. In addition,
we still have an "network thread", which is wakeup by an interrupt.
The thread wakeups all waiting future. If no future is available,
the thread calls directly the IP stack.
stlankes added a commit to stlankes/hermit-rs that referenced this pull request Aug 2, 2021
@stlankes
revise network integration and add support of futures
ecb43e2 
smoltcp 0.7 provides async/await waker support (smoltcp-rs/smoltcp#394).
I followed the example implementation https://github.com/embassy-rs/embassy/tree/net/embassy-net
to add waker support in hermit-sys.

However, hermit-sys can be used in a multi-threaded applications.
Consequently, the implementation must be thread safed. In addition,
we still have an "network thread", which is wakeup by an interrupt.
The thread wakeups all waiting future. If no future is available,
the thread calls directly the IP stack.
stlankes added a commit to hermit-os/hermit-rs that referenced this pull request Aug 7, 2021
@stlankes
revise network integration and add support of futures
32aa462 
smoltcp 0.7 provides async/await waker support (smoltcp-rs/smoltcp#394).
I followed the example implementation https://github.com/embassy-rs/embassy/tree/net/embassy-net
to add waker support in hermit-sys.

However, hermit-sys can be used in a multi-threaded applications.
Consequently, the implementation must be thread safed. In addition,
we still have an "network thread", which is wakeup by an interrupt.
The thread wakeups all waiting future. If no future is available,
the thread calls directly the IP stack.
stlankes added a commit to hermit-os/hermit-rs that referenced this pull request Aug 7, 2021
@stlankes
revise network integration and add support of futures
d9510ed 
smoltcp 0.7 provides async/await waker support (smoltcp-rs/smoltcp#394).
I followed the example implementation https://github.com/embassy-rs/embassy/tree/net/embassy-net
to add waker support in hermit-sys.

However, hermit-sys can be used in a multi-threaded applications.
Consequently, the implementation must be thread safed. In addition,
we still have an "network thread", which is wakeup by an interrupt.
The thread wakeups all waiting future. If no future is available,
the thread calls directly the IP stack.
@Dirbaio
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Dirbaio commented Dec 11, 2021

Now moved here https://github.com/embassy-rs/embassy/blob/master/embassy-net/src/tcp_socket.rs

@ivmarkov ivmarkov mentioned this pull request May 1, 2022
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@cameronelliott
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This example link shouldn't break unless they re-write history:

https://github.com/embassy-rs/embassy/blob/79cbad501c6e6166d0e53ab33b2401a674ee9f31/embassy-net/src/tcp_socket.rs#L23

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