Re: [RFC PATCH 06/13] m68k: Drop ARCH_USES_GETTIMEOFFSET

From: Finn Thain
Date: Tue Nov 13 2018 - 01:14:54 EST


On Tue, 13 Nov 2018, Michael Schmitz wrote:

>
> > (It appears that a QEMU-emulated Mac does not benefit from having a
> > clocksource that's more accurate than the 'jiffies' clocksource, in
> > spite of "clocksource: Switched to clocksource via1".)
>
> With the current code, kernel log timestamps have 10 ms resolution on
> Atari. Time resolution of times reported by initcall_debug is roughly 40
> us. I'd expect that changes with falling back to jiffies only. Might be
> worth a try on QEMU Mac.

The initcall debug output shows the same precision as my earlier tests
with userland. The VIA timer only gets updated when QEMU wants to update
it, which seems to be about every 9765 us. Hence, using the 'jiffies'
clocksource would be effectively no regression for a virtual Mac.

--