Red Hat Bugzilla – Bug 489494
F12: enable CONFIG_RTC_HCTOSYS
Last modified: 2009-09-02 09:46:19 EDT
Description of problem:
The latest hwclock(8) (from util-linux-ng 2.15, probably in Fedora-12) has a new option --systz (set TZ only) that is possible to use instead --hctosys when system clock time is already set from the hardware clock by the kernel (when compiled with CONFIG_RTC_HCTOSYS).
For example Ubuntu 9.04 is planning to use this feature to speed up userspace boot process. (The "hwclock --hctosys" is very tricky...) It would be nice to test it in (F-12) rawhide.
Note that this change requires to update the RTC udev rule.
$ rpm -qf /lib/udev/rules.d/88-clock.rules
How would you write the rule to DTRT depending on how the kernel is configured?
once we have a util-linux-ng in the tree that supports it, we can make this change. Until then, changing it sounds like a bad idea.
(In reply to comment #3)
> Until then, changing it sounds like a bad idea.
Sure. I agree. I'll ping you :-)
Dave, ping :-)
The hwclock that supports CONFIG_RTC_HCTOSYS is already in rawhide (F-12).
I must add in the discussion here that this feature is much wanted for kvm guests. The problem there is that the hypervisor will set guest's wall time, but hwclock will supersede this reading.
The value should be the same, but the trip to the emulated cmos is a very lengthy one, and by the time all hwclock tricks are done, 1 or 2 seconds (some users even report 3) has passed. Much wanted feature for F12 virt.
we changed this in rawhide a while ago.