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DXist / boot-time

Suspend-aware monotonic time for Rust
MIT License
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Using boottime crate for timers and timeouts? #2

Open link2xt opened 10 months ago

link2xt commented 10 months ago

This crate allows to measure time, but can it be used as a replacement for std clocks to create timers? E.g. as suggested in https://github.com/tokio-rs/tokio/issues/3185

I think it is not possible, but would be nice to get a confirmation. To close the issue I suggest writing this in the README so potential users know whether this crate solves their problem or not.

DXist commented 10 months ago

@link2txt, the interface is the same as std::time::Instant so client code could use it as a replacement to implement suspend-aware timers in best effort manner.

I've decided to create this crate to support boot time in the completion-style IO driver.

But it's used only for Windows (IOCP) and BSD-like targets (kqueue). Linux implementation (io_uring) sets the native CLOCK_BOOTTIME flag for Timeout op and relies on kernel-side high resolution timers.

To answer the question whether this crate solves potential users problem - it depends on the used OS primitives.

For Linux and io_uring there is no problem at all. For other platforms this crate could be used as a fallback.

Tokarak commented 9 months ago

Is there a way for this crate to be "dropped in" into Tokio's sleep function (as well as other functions) without forking Tokio? I tried to pass this crate's implementation of Duration to Tokio, but that didn't work. Note: here is my code https://github.com/redlib-org/redlib/pull/23

DXist commented 9 months ago

Support of suspend-aware timers depends not on this crate but on used system interfaces. Tokio uses Mio as IO backend. Mio doesn't use IOCP on Windows nor Timeout operation on Linux+io_uring.

As I mentioned earlier this crate is not needed on Linux/io_uring when kernel side timers are used. I've used this crate in application-side timer wheel for IOCP/kqueue backends.