time(1p) equivalent #123

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emma · 2024-06-21T02:22:33-06:00

emma commented

2024-06-21 02:22:33 -06:00

We need a utility that can test the length of time a line of shell takes to complete execution and output data formatted as ASV.

emma added the

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labels 2024-06-21 02:22:33 -06:00

trinity commented

2024-06-24 20:37:14 -06:00

I think this should be a separate utility and not a shell built-in. This would just be an exec(2) and a couple timer calls, right? How precise does this need to be?

trinity commented

2024-07-19 17:01:48 -06:00

Would a simple wrapper around https://doc.rust-lang.org/std/time/struct.SystemTime.html suffice?

sashakoshka commented

2024-07-19 21:01:33 -06:00

I think this should be a separate utility and not a shell built-in. This would just be an exec(2) and a couple timer calls, right? How precise does this need to be?

Having it be a shell builtin would not grant more precision, so I'd say yes. As for how precise, in bash, time outputs values in millisecond precision. It should achieve that at least.

> I think this should be a separate utility and not a shell built-in. This would just be an exec(2) and a couple timer calls, right? How precise does this need to be? Having it be a shell builtin would not grant more precision, so I'd say yes. As for how precise, in bash, time outputs values in millisecond precision. It should achieve that at least.

sashakoshka commented

2024-07-19 21:04:31 -06:00

Would a simple wrapper around https://doc.rust-lang.org/std/time/struct.SystemTime.html suffice?

From the doc:

Distinct from the Instant type, this time measurement is not monotonic. This means that you can save a file to the file system, then save another file to the file system, and the second file has a SystemTime measurement earlier than the first. In other words, an operation that happens after another operation in real time may have an earlier SystemTime!

So probably not. If the system clock changes while the command is running, the output would be erroneous. This ought to be used instead: https://doc.rust-lang.org/std/time/struct.Instant.html

> Would a simple wrapper around https://doc.rust-lang.org/std/time/struct.SystemTime.html suffice? From the doc: > Distinct from the Instant type, this time measurement is not monotonic. This means that you can save a file to the file system, then save another file to the file system, and the second file has a SystemTime measurement earlier than the first. In other words, an operation that happens after another operation in real time may have an earlier SystemTime! So probably not. If the system clock changes while the command is running, the output would be erroneous. This ought to be used instead: https://doc.rust-lang.org/std/time/struct.Instant.html

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