Stabilize div_duration

[newpavlov]

Closes #63139

[rustbot]

r? @jhpratt

rustbot has assigned @jhpratt.
They will have a look at your PR within the next two weeks and either review your PR or reassign to another reviewer.

Use r? to explicitly pick a reviewer

[jhpratt]

This still needs FCP. Nominating for T-libs-api so they'll see it.

[joshtriplett]

We discussed this in today's @rust-lang/libs-api meeting. We were generally favorable towards adding these. But also, multiple people expressed a preference that these could be more accurate by doing the math in nanos rather than seconds.

That said:

@rfcbot merge

[rfcbot]

Team member @joshtriplett has proposed to merge this. The next step is review by the rest of the tagged team members:

• @Amanieu
• @BurntSushi
• @dtolnay
• @joshtriplett
• @m-ou-se

No concerns currently listed.

Once a majority of reviewers approve (and at most 2 approvals are outstanding), this will enter its final comment period. If you spot a major issue that hasn't been raised at any point in this process, please speak up!

See this document for info about what commands tagged team members can give me.

[newpavlov]

these could be more accurate by doing the math in nanos rather than seconds

Hm, comparing the two expressions:

let s1 = (d1.secs as f32) + (d1.nanos as f32) / (NANOS_PER_SEC as f32);
let s2 = (d2.secs as f32) + (d2.nanos as f32) / (NANOS_PER_SEC as f32);
s1 / s2

let s1 = (d1.secs as f32) * (NANOS_PER_SEC as f32) + (d1.nanos as f32);
let s2 = (d2.secs as f32) * (NANOS_PER_SEC as f32) + (d2.nanos as f32);
s1 / s2

I guess the latter should be indeed slightly more accurate. The former will often lose precision in the nanos division, while in the latter case, if loss of precision has happened during multiplication, addition of nanos is unlikely to change the final result.

Should I replace the methods implementation?

[rfcbot]

🔔 This is now entering its final comment period, as per the review above. 🔔

[jhpratt]

Should I replace the methods implementation?

I'm indifferent. The time crate divides the nanoseconds as integers, just as the current implementation in std does. At most I'd imagine this would only differ by a single nanosecond, but I haven't checked that.

[rfcbot]

The final comment period, with a disposition to merge, as per the review above, is now complete.

As the automated representative of the governance process, I would like to thank the author for their work and everyone else who contributed.

This will be merged soon.

[jhpratt]

@bors r+

[bors]

📌 Commit 8da41b1 has been approved by jhpratt

It is now in the queue for this repository.