Specialize sleep_until implementation for unix (except mac) #141829

dvdsk · 2025-05-31T19:38:39Z

related tracking issue: #113752
Supersedes #118480 for the reasons see: #113752 (comment)

Replaces the generic catch all implementation with target_os specific ones for: linux/netbsd/freebsd/android/solaris/illumos etc. Other platforms like wasi, macos/ios/tvos/watchos and windows will follow in later separate PR's (once this is merged).

rustbot · 2025-05-31T19:38:43Z

r? @tgross35

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dvdsk · 2025-05-31T19:39:32Z

r? @cuviper

dvdsk · 2025-05-31T22:38:40Z

This can be done without touching all pal's, ill be doing that tomorrow, now its bed time 😴

edit: I was mistaken, tidy does not allow #[cfg(...)] in strc/thread/mod.rs probably for a good reason. Therefore we need a trivial not platform specific sleep_until in every pal that does not have a specialized one.

- In contradiction to nanosleep clock_nanosleep returns the error directly and does not require a call to `os::errno()`. - The last argument to clock_nanosleep can be NULL removing the need for mutating the timespec. - Missed an `allow(unused)` that could be made conditional.

This is intended to support the std's new sleep_until. Only the clocks REALTIME and MONOTONIC are supported. The first because it was trivial to add the second as its needed for sleep_until. Only passing no flags or passing only TIMER_ABSTIME is supported. If an unsupported flags or clocks are passed this implementation panics.

src/tools/miri/src/shims/time.rs

dvdsk · 2025-07-03T19:57:34Z

rebased to:

fix commit formatting unrelated MIRI code.
fix spell errors for months ago without adding new useless commit

edit: I just realized rebasing all the time makes this rather hard to review. I'll rebase/squash at the end, for now I'll focus on short descriptive commits.

RalfJung · 2025-07-03T20:25:45Z

src/tools/miri/src/shims/time.rs

@@ -396,14 +393,14 @@ pub trait EvalContextExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
            // No flags set, the timespec should be interperted as a duration
            // to sleep for
            TimeoutAnchor::Relative
-        } else if flag == this.eval_libc("TIMER_ABSTIME").to_int(int_size) {
+        } else if flags == this.eval_libc("TIMER_ABSTIME").to_i32()? {


Suggested change

} else if flags == this.eval_libc("TIMER_ABSTIME").to_i32()? {

} else if flags == this.eval_libc_i32("TIMER_ABSTIME") {

RalfJung · 2025-07-05T07:43:27Z

src/tools/miri/tests/pass-dep/libc/libc-time.rs

+    test_nanosleep();
+    test_clock_nanosleep_absolute();
+    test_clock_nanosleep_relative();
+    test_localtime_r_epoch();
    test_localtime_r_gmt();
    test_localtime_r_pst();


Not sure why you reordered an existing test here?^^

Since the other tests are all about getting the current time, seems best to have the sleep tests all together in a separate "section", e.g. at the end of main, separated from the existing tests.

Not sure why you reordered an existing test here?^^

I really need to start paying a little more attention to the diffs I make

Since the other tests are all about getting the current time, seems best to have the sleep tests all together in a separate "section", e.g. at the end of main, separated from the existing tests.

Good idea

RalfJung · 2025-07-05T07:47:55Z

src/tools/miri/tests/pass-dep/libc/libc-time.rs

+        let mut ts = timespec_now(libc::CLOCK_MONOTONIC);
+        ts.tv_nsec += 1_000_000_000 / 10;
+        ts
+    };


Needs logic to deal with nsec growing to more than 1s

RalfJung · 2025-07-05T07:51:46Z

src/tools/miri/tests/pass-dep/libc/libc-time.rs

+    unsafe { timespec.assume_init() }
+}
+
+fn test_clock_nanosleep_absolute() {


These functions also need the cfg to not be built on macOS.

You can test this locally even if you are not on macOS:

./x test miri --target aarch64-apple-darwin -- time

You can test this locally even if you are not on macOS:

that's super useful thanks!

RalfJung · 2025-07-05T09:38:33Z

@rustbot author
based on review

rustbot · 2025-07-05T09:38:37Z

Reminder, once the PR becomes ready for a review, use @rustbot ready.

dvdsk · 2025-07-05T10:15:58Z

@rustbot ready

Apologies for the unnecessary rebase.

Changes:

Moved clock_nanosleep tests in libc-time.rs to their own module. That module is only compiled for platforms supporting clock_nanosleep
Call the tests for clock_nanosleep at the end of the main
Adds a helper for adding 100ms to a timespec that handles nsec growing beyond 1s
Undo the accidental change to test call order in main (libc-time.rs)
Use eval_libc_i32 for getting the value for flag TIMER_ABSTIME

RalfJung · 2025-07-05T10:37:09Z

src/tools/miri/tests/pass-dep/libc/libc-time.rs

+        ts.tv_nsec = ts.tv_nsec % SECOND;
+        ts.tv_sec = ts.tv_nsec / SECOND;


This doesn't do the right thing. You need to swap these two lines. With your version of the code, tv_sec will always end up being 0.

Oh, also this should be tv_sec += ...!

RalfJung · 2025-07-05T10:37:21Z

src/tools/miri/tests/pass-dep/libc/libc-time.rs

+    }
+
+    /// Helper function to get the current time for testing relative sleeps
+    fn timespec_now(clock: libc::clockid_t) -> libc::timespec {


Please put the 2 helper functions above the functions that use them.

rustbot assigned tgross35 May 31, 2025

rustbot assigned cuviper and unassigned tgross35 May 31, 2025

dvdsk mentioned this pull request May 31, 2025

Specialize sleep_until implementation #118480

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workingjubilee changed the title ~~Specialize sleep_until implementation for unix (expect mac)~~ Specialize sleep_until implementation for unix (except mac) May 31, 2025

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dvdsk force-pushed the sleep_until_linux branch from 8010ec8 to 295e8d1 Compare May 31, 2025 19:54

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dvdsk force-pushed the sleep_until_linux branch from 1e7d958 to 406e32b Compare May 31, 2025 21:31

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dvdsk marked this pull request as draft May 31, 2025 22:37

rustbot added the O-wasm Target: WASM (WebAssembly), http://webassembly.org/ label Jun 1, 2025

dvdsk force-pushed the sleep_until_linux branch from 4bcfd27 to f657ec1 Compare June 1, 2025 07:08

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dvdsk force-pushed the sleep_until_linux branch from f657ec1 to 1127a50 Compare June 1, 2025 07:26

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dvdsk force-pushed the sleep_until_linux branch from 1127a50 to 60edd5a Compare June 1, 2025 07:35

dvdsk added 4 commits July 3, 2025 21:20

fixes missing import for platform unsupported

e69a490

Adhere to Miri code standards, fixes using host constants/types

dcb3593

dvdsk force-pushed the sleep_until_linux branch from d91e6a9 to dcb3593 Compare July 3, 2025 19:20

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RalfJung reviewed Jul 3, 2025

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fix read_scalar/read_pointer

f07f99c

RalfJung reviewed Jul 3, 2025

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rename clock_nanosleep argument

2645080

dvdsk force-pushed the sleep_until_linux branch from 7c039f4 to 2645080 Compare July 4, 2025 18:41

dvdsk added 4 commits July 4, 2025 21:29

use eval_libc_i32 instead of .to_i32()

1ca609d

shim tests adds nanosleep and clock nanosleep

e5b28af

add sleep_until test

c5a13dd

change test sleep duration from 1s to 100ms

dbe9e85

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only run clock_nanosleep tests on support target_os

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RalfJung reviewed Jul 5, 2025

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rustbot added S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Jul 5, 2025

clock_nanosleep tests behind cfg + handle tv.nsec > 1s

d3f167f

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RalfJung reviewed Jul 5, 2025

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	} else if flags == this.eval_libc("TIMER_ABSTIME").to_i32()? {
	} else if flags == this.eval_libc_i32("TIMER_ABSTIME") {

		ts.tv_nsec = ts.tv_nsec % SECOND;
		ts.tv_sec = ts.tv_nsec / SECOND;

Specialize sleep_until implementation for unix (except mac) #141829

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Specialize sleep_until implementation for unix (except mac) #141829

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dvdsk commented May 31, 2025 •

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