sysctl -a is slow

[jhell]

On Mon, 20 Sep 2010 10:26, David Xu wrote:
In Message-Id: <4C976F14.8000408 at freebsd.org>

> jhell wrote:
>> On 09/19/2010 09:28, David Xu wrote:
>>> just typed sysctl -a on keyboard, and found it is slow, sometimes
>>> it has been stuck for a few seconds, further studied,I found it is
>>> stucked at sysctl kern.geom:
>>> 
>>> %/usr/bin/time sysctl -a kern.geom
>>> kern.geom.collectstats: 1
>>> kern.geom.debugflags: 0
>>> kern.geom.label.debug: 0
>>> kern.geom.label.ext2fs.enable: 1
>>> kern.geom.label.iso9660.enable: 1
>>> kern.geom.label.msdosfs.enable: 1
>>> kern.geom.label.ntfs.enable: 1
>>> kern.geom.label.reiserfs.enable: 1
>>> kern.geom.label.ufs.enable: 1
>>> kern.geom.label.ufsid.enable: 1
>>> kern.geom.label.gptid.enable: 1
>>> kern.geom.label.gpt.enable: 1
>>>        2.01 real         0.00 user         0.00 sys
>>> 
>>> it seems it needs more than 2 seconds to complete.
>>> 
>> 
>> A ktrace(1) and a kdump(1) of the resulting ktrace.out file would
>> probably help here along with uname -a. Ive seen this happen once before
>> but do not recall what caused it.
>> 
>> 
>> Regards & good luck,
>> 
>
> Result is dumped here.
> http://people.freebsd.org/~davidxu/sysctl_slow.txt
> I think the culprit is sysctl kern.geom.confdot,
> which does not appear in normal output, until I check the kdump result.
> I tried five times, and it was blocked three times.
>


Inspecting the output of sysctl -b kern.geom.confdot will give you what 
you currently have configured in the system as disks and what not through 
geom. If this seems to be bailing at that point, which is an opaque 
MIB/OID which doesn't come up other than when you use the "-o" switch to 
sysctl(1) then could you check your labels for your disks for any weird 
characters in the labels ?

( sysctl -bo kern.geom )

Also does this have the same effect when run in a xterm, cons25 terminal ?

And same for the above but with the C, *_COUNTRY.UTF-8 or your normal 
locale ?

( env LANG=C sysctl kern.geom )

Looking at the output from mine there are quite a few unprintable 
characters present. Maybe these are having an impact with one of your 
labels.


-- 

  jhell,v