>I admit I only briefly looked at the latest code, but afaik >especially with the 'demand timer patch' Linux uses the TOD >to tell time, and I don't recall seeing the drift corrections >applied. This would mean an ntpd cannot adjust time of Linux >running on z/VM, but one might be able to change that. I can >even imagine hwclock to issue SCK instruction to update the >virtual machine's private offset of the VM TOD clock (to >live through a reboot, but not logoff).
You have looked very briefly ;-) Linux uses the TOD clock to set the internal xtime at ipl. Afterwards Linux uses the clock comparator to get an interrupt every 1/100 second. In the interrupt handler this "tick" is added to xtime by calling the common code function do_timer(). This is where ntp time adjustment is taking place as well. It is completly indepedent from the architecture. The timer patch optimizes the code a bit so that it can account for more than a single tick in one go. This is the basic idea behind the timer patch: stop the HZ timer until something relevant happens and then catch up with the ticks/xtime. In short the ntpd time adjustment should work just fine on s/390. blue skies, Martin Linux/390 Design & Development, IBM Deutschland Entwicklung GmbH Sch�naicherstr. 220, D-71032 B�blingen, Telefon: 49 - (0)7031 - 16-2247 E-Mail: [EMAIL PROTECTED]
