3 ms·
> 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 cu
by cyphar 8y ago
> 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 8y agoYou 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.