On Friday 13 March 2009, Frans Pop wrote: > I added printks that show changes in clock data. I print info for > 3 consecutive calls of update_wall_time every 1000 times the function > is called and also after a change of clock source. Aaarghh. I'm a moron, but most of you will already have concluded that by now. I've been looking at nsecs as if they also included secs. So, here's a trace with Roman's patches that really shows the relevant data. Basic conclusion remains the same though: time really does look to be running backwards in the very early part of the boot because the seconds are not advancing while the nsecs are going backwards. 0.004688! jiffies/8 (1): xtime.tv: 1236962306/99461000 -> 1236962306/99461001 0.004793! clock->xtime: 0 -> -256, error: 0 -> -4294867296 0.009705! jiffies/8 (2): xtime.tv: 1236962306/99461001 -> 1236962306/99444618 0.009821! clock->xtime: -256 -> -256, error: -4294867296 -> -4292501984672096 0.014514! Inode-cache hash table entries: 16384 (order: 4, 65536 bytes) 0.014944! jiffies/8 (3): xtime.tv: 1236962306/99444618 -> 1236962306/99395467 0.015067! clock->xtime: -256 -> -256, error: -4292501984672096 -> -12807124325236736 0.019704! jiffies/8 (4): xtime.tv: 1236962306/99395467 -> 1236962306/99379084 0.019811! clock->xtime: -256 -> -256, error: -12807124325236736 -> -14918180945433952 0.140556! Memory: 251008k/262144k available (2144k kernel code, 0k reserved, 897k data, 152k init) 0.140913! Write protected kernel read-only data: 0x12000 - 0x2d8fff 0.143231! Calibrating delay loop (skipped)... 572.00 BogoMIPS preset 0.144675! Security Framework initialized 0.144870! SELinux: Disabled at boot. 0.146009! Mount-cache hash table entries: 512 0.152474! Initializing cgroup subsys ns 0.152671! Initializing cgroup subsys cpuacct 0.153095! Initializing cgroup subsys devices 0.154303! init: calling smp_prepare_cpus 0.189342! CPUs: 2 configured, 0 standby 0.189516! s390_smp: smp_detect_cpus calling get_online_cpus 0.189742! s390_smp: smp_detect_cpus calling __smp_rescan_cpus 0.189964! s390_smp: smp_rescan_cpus_sigp starting loop [... System hangs here ...] [... By this time it looks like the error has stabilized somewhat and nsecs are more stable ...] [... nsecs are actually larger now than in the display at 0.019704 ...] 0.311447! jiffies/8 (153): xtime.tv: 1236962306/599346640 -> 1236962306/599346640 0.311567! clock->xtime: -228 -> -29, error: -16490881133476192 -> -16490883213850976 0.312174! jiffies/8 (154): xtime.tv: 1236962306/599346640 -> 1236962306/599346641 0.312292! clock->xtime: -29 -> -226, error: -16490883213850976 -> -16490885428443488 0.312884! jiffies/8 (155): xtime.tv: 1236962306/599346641 -> 1236962306/599346641 0.313014! clock->xtime: -226 -> -31, error: -16490885428443488 -> -16490887508818272 [... Only here do seconds start to increase ...] 0.320129! jiffies/8 (304): xtime.tv: 1236962307/99331656 -> 1236962307/99331656 0.320254! clock->xtime: -201 -> -56, error: -16426767068861792 -> -16426769149236576 0.320844! jiffies/8 (305): xtime.tv: 1236962307/99331656 -> 1236962307/99331657 0.320954! clock->xtime: -56 -> -199, error: -16426769149236576 -> -16426781363829088 0.321536! jiffies/8 (306): xtime.tv: 1236962307/99331657 -> 1236962307/99331657 0.321651! clock->xtime: -199 -> -58, error: -16426781363829088 -> -16426783444203872 0.328758! jiffies/8 (455): xtime.tv: 1236962307/599316731 -> 1236962307/599316732 0.328876! clock->xtime: -82 -> -173, error: -16362926407417856 -> -16362928622010368 0.329470! jiffies/8 (456): xtime.tv: 1236962307/599316732 -> 1236962307/599316732 0.329598! clock->xtime: -173 -> -84, error: -16362928622010368 -> -16362920702285152 0.330192! jiffies/8 (457): xtime.tv: 1236962307/599316732 -> 1236962307/599316733 0.330317! clock->xtime: -84 -> -171, error: -16362920702285152 -> -16362922916877664 0.374500! jiffies/8 (1456): xtime.tv: 1236962311/599199308 -> 1236962311/599199308 0.374632! clock->xtime: -165 -> -92, error: -15860566497065312 -> -15860568577440096 -- To unsubscribe from this list: send the line "unsubscribe linux-s390" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html