On Fri, May 20, 2011 at 02:06:21PM +0200, corentin.labbe wrote:
>
> This patch add the -H option to dmesg which allow to print human
> readable time instead of the number of seconds since boot.
Nice idea, but it's not so simple :-(
The time stamp used for printk() is not based on normal system time
(as you know from gettimeofday()). It uses cpu_clock() (IMHO to
keep printk() robust and without xtime_lock).
The problem is that the cpu_clock is not updated after system resume,
so if you suspend (e.g. pm-suspend(8)) and resume than the dmesg -H
command prints nonsenses...
For example (copy & past from /var/log/messages):
Jun 27 23:39:53 nb kernel: [50065.238635] PM: Syncing filesystems ... done.
Jun 28 20:23:29 nb kernel: [50065.284226] Freezing user space processes ... (elapsed 0.09 seconds) done.
^^^^^
The first line is before suspend and second is after resume. The time
stamp [50065.xxxxxx] is still the same although the system was
suspended for almost whole day.
The same system, the latest kernel message:
# date
Wed Jun 29 16:29:28 CEST 2011
# mount /dev/sdb1 /mnt/test
# ./sys-utils/dmesg -H | tail -1
[Tue Jun 28 11:10:41 2011] EXT4-fs (sdb1): mounted filesystem with ordered data mode. Opts: (null)
Karel
--
To unsubscribe from this list: send the line "unsubscribe util-linux" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
