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List:       evlog-developers
Subject:    Re: [evlog-dev] GMT time on evlog timestamps?
From:       "Hien Q Nguyen" <nguyhien () us ! ibm ! com>
Date:       2001-12-13 22:48:39
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                                                                                      \
                
                      Hien Q Nguyen                                                   \
                
                                               To:       Larry Kessler/Beaverton/IBM  \
                
                      12/13/2001 02:12         cc:                                    \
                
                      PM                       From:     Hien Q \
                Nguyen/Beaverton/IBM@IBMUS                                            \
                
                                               Subject:  How does it look?            \
                
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The problem has been fixed.
We observed the problem and found that the kernel global xtime
(system time) initially is
xtime.nsec = zero, and little later....
xtime.nsec = cmos_time, then as soon as the filesystem is initialized....
xtime.nsec = cmos_time + timezone adjustment

The Fix....
We now timestamp all kernel events with the cmos time (whatever is in the
cmos) when we first put the event record in the kernel buffer.  This time
will
be adjusted to UTC when the log daemon reads the event from the
kernel buffer, and writes the event to the log file.   Affectively, the
logged
time value is equal to the number of ticks since the Epoch (UTC)
which is what we want (and matches the proposed POSIX standard).
However, when the evlview command reads the event, it will display
the timestamp as the local time.

Both kernel and user changes are needed to fix this problem.
The files that are effected by the changes are (in the source tree):
  evlog/kernel/v2.4.x/evl_cmd.c
  evlog/user/cmd/evlogd/evlogd.c

We are planning to include this fix in the next release (exact date is
TBD),
but in the meantime...
1) User needs to copy the evl_cmd.c to their kernel source
    (ie. /usr/src/linux/kernel) and rebuild and install the new kernel.
2) User also needs to rebuild the log daemon, copy the evlogd.c to
     evlog/user/cmd/evlogd/evlogd.c and do...
             cd evlog/user
              make
              make install
              make startall
     to apply the change.


Hien Nguyen
nguyhien@us.ibm.com
(503) 578-4347


> ---------+-------------------------------------------->
> > "Brinkman, David N"              |
> > <david.n.brinkman@intel.com>     |
> > Sent by:                         |
> > evlog-developers-admin@lists.sour|
> > ceforge.net                      |
> > > 
> > > 
> > 12/11/2001 07:16 AM              |
> > > 
> ---------+-------------------------------------------->
  >-------------------------------------------------------------------------------------------------|
  |                                                                                   \
|  |       To:       evlog-developers@lists.sourceforge.net                           \
|  |       cc:                                                                        \
|  |       Subject:  [evlog-dev] GMT time on evlog timestamps?                        \
|  |                                                                                  \
|  |                                                                                  \
|  >-------------------------------------------------------------------------------------------------|




Has anyone noticed that the kernel messages (from printk and
posix_log_printf) that
are logged to the evlog during system startup, but before evlogd startup,
have what appears to
be GMT time. I'm in the EST timezone and we are seeing a 5 hour time
difference on these boot
up messages. The timestamp does not include a timezone so this could lead
to
unexpected
results when doing a time ("age") query?  Is this a known
problem/limitation
or could it
be a system configuration issue? I see that syslog gets the correct time
(in
/var/log/messages)
on the same printk messages.

Thanks
David


David Brinkman
Software Engineer                                Office:803.461.6104
Telecom Server Development                       Fax: 803.461.6292
Enterprise Platforms & Services Division

Intel Corporation
Columbia Design Center, CBA-2
Synergy Business Park
250 Berry Hill Road, Suite 100
Columbia, SC 29210
USA



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