On Tue, Apr 05, 2011 at 11:23:34PM +0100, Ed W wrote: > OK, so I have chrony built in a uclibc chroot with /usr/src/linux holding a > 32bit kernel with HZ set to 1024 (I think). The host is a 64bit kernel with > HZ set to 250 - however, I don't think this should be relevant? > > This is then installed on my Alix (32bit only). If I set "linux_hz 1024" in > my conf file I get:
> Apr 5 22:05:37 localhost user.info chronyd[3457]: set_config_hz=1 hz=1024 > shift_hz=7 basic_freq_scale=0.12500000 nominal_tick=977 slew_delta_tick=81 > max_tick_bias=97 > My question is why I see "hz=100" and why the 1024 config causes the fatal > error? Because the userspace and kernel HZ are different. The userspace HZ is scaled so it's constant on a given architecture to avoid problems with applications assuming a fixed HZ. The hz value is needed to determine tick values which are valid in the adjtimex() call. If nominal_tick and max_tick_bias are incorrect, you may get the fatal error when chrony is trying to compensate for a large frequency offset or fast slewing. > I'm fairly sure I was still getting hz=100 in the logs when built against a > kernel source using 1000hz and 250hz. Also I only looked at the config code > quickly, but I can't see where it's trying to read the kernel HZ value at > compile time? The hz value is determined at start from the current tick value, it's assumed to be 100 or a power of 2. > Note, seems to be working fine without any config stanzas, I just thought it > curious? Yes, keep it at 100 :). -- Miroslav Lichvar --- To unsubscribe email chrony-users-requ...@chrony.tuxfamily.org with "unsubscribe" in the subject. For help email chrony-users-requ...@chrony.tuxfamily.org with "help" in the subject. Trouble? Email listmas...@chrony.tuxfamily.org.
