Re: PSA: Clock drift and pkgin

[Jonathan Stone <kiwi_jonathan%yahoo.com@localhost>]

On Saturday, December 23, 2023 at 10:19:53 PM PST, Simon Burge <simonb%netbsd.org@localhost> wrote:



> I have a grotty hack that attempted to spin if the requested timeout
> was less than a tick based on what DragonflyBSD does.  It mostly
> worked for simple tests but I haven't tested it seriously.  It's at
> https://www.NetBSD.org/~simonb/pollfixhack.diff .

is that really viable on uniprocessor machines?

> This is potentially
>another direction until we get a pure tickless kernel...

You can only do tickless if you can track how much time is elapsing when no ticks fire, or none are pending.
I don't see how to do that without a high-res timer like a CPU cycle counter, or I/O bus cycle counter,
or what-have-you. Gong fully tickless would therefore end support for machines without such a timer.
Is NetBSD ready to do that?