[ntp:questions] Ntpd in uninterruptible sleep?

A C agcarver+ntp at acarver.net
Tue Oct 25 22:56:23 UTC 2011


On 10/25/2011 14:53, unruh wrote:
> On 2011-10-25, A C<agcarver+ntp at acarver.net>  wrote:
>> On 10/25/2011 02:06, Uwe Klein wrote:
>>> A C wrote:
>>>> On 10/24/2011 16:04, Richard B. Gilbert wrote:
>>>>
>>>>>
>>>>> 64MB is not a lot of RAM by today's standards. Can you install more for
>>>>> testing purposes?
>>>>
>>>>
>>>> Unfortunately not. There are only four slots and I don't have any
>>>> sticks larger than 16MB so 64 is it for now. However, for the little
>>>> that the machine does (it's only job is ntpd and gpsd) I think 64
>>>> should be adequate.
>>> Heheh, still got my MVME167 with 8MB of RAM running SysVR3.6.
>>>
>>> Are you using the local machine as X-Display?
>>>
>>> Can you go down to a nongraphical runstate and
>>> work via a remote (telnet) session from another box?
>>>
>>> If nothing else works kill the wedged process hard
>>> to create a core dump?
>>
>> I am not using local graphics.  There is no desktop environment in use
>> on this machine at all.  In fact there is no monitor on the machine (at
>> least not full time).  My Xterm and Xclock are exported to a remote machine.
>
> ?? So why are you using X at all? Xterm can surely be replaced by the
> console. And xclock by running date to tell you what time the machine
> thinks it is (I assume you use that to check to see if ntpd has stopped
> controlling the clock)

A few reasons for not using console:
1. I don't have a monitor to devote to the machine that works at 
standard Sun framebuffer refresh rates.  With the odd resolution and 
rate of the CG6 most inexpensive LCDs just fall over and refuse to sync. 
  My one monitor that can sync is also the nice one that I use for my 
regular desktop machine.

2. Even with a monitor on the machine there's a bug in the console 
driver in NetBSD that locks up the console getty if redraws occur too 
quickly.  It's a known bug on the sparc hardware but hard to track down. 
  It doesn't affect anything else except the getty on the console.

3. I can leave the Xterm on my screen on my everyday machine and be able 
to use it when I need to without needing to reach for another keyboard. 
  Plus anything I do on the machine, especially during debugging right 
now, I can copy and paste to post to the list or save for later.

You are mostly correct about Xclock, it's just there to tell me when the 
machine simply dies while I'm debugging these lockup issues.  I wouldn't 
usually have the clock up and running but right now it comes in handy 
for verifying that the network/kernel/base system is still running. 
Checking ntpd happens via another machine and ntpq.  It's my intent to 
have a cron poll once every few hours, make sure all is good, and fire 
off an email warning if it's not.  If I can get ntpd and this machine to 
behave I'll probably never have an email and it can sit quietly keeping 
time for my network.


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