[cyphar]

> This proposal implements clock offsets, but does it support continuous time scaling?

No. The main reason why is because it's very difficult to do with the current time-keeping machinery within the kernel. Some people also want the ability to freeze the current time, which is also similarly difficult -- and in some cases harder because then what should CLOCK_MONATONIC give you? There's also the fact that there's currently no interface to set the "clock speed" do any of these things.

Making time go backwards I think would simply be impossible, due to how many things in the kernel that interact with time probably make the (reasonable) assumption that time goes forwards. Also CLOCK_MONATONIC would do the exact opposite in such circumstances.

[cperciva]

You mean "CLOCK_MONOTONIC", not "CLOCK_MONATONIC". (I'm guessing this is a misspelling, not a typo, since it appeared twice.)

And the simple answer is that if time stops then CLOCK_MONOTONIC always returns the same time. This is perfectly fine given correct software; CLOCK_MONOTONIC is guaranteed to not go backwards but it it not guaranteed to always go forward. One could imagine for example a system with a very inaccurate clock where CLOCK_MONOTONIC simply counts days, for example.