Dmesg is not showing whole boot list

Dmesg is not showing whole boot list

[CIJOML]

Hello,

maybe this si a wrong list to ask, bug after boot, dmesg shows that few lines 
at the beginning are missing.

Is there any option I can increase to get full dmesg?

ine.. 4801.43 BogoMIPS (lpj=2400718)
Security Framework v1.0.0 initialized
SELinux:  Initializing.
SELinux:  Starting in permissive mode
Mount-cache hash table entries: 512
CPU: After generic identify, caps: bfebfbff 00000000 00000000 00000000 
00004400 00000000 00000000
CPU: After vendor identify, caps: bfebfbff 00000000 00000000 00000000 00004400 
00000000 00000000
CPU: Trace cache: 12K uops, L1 D cache: 8K
CPU: L2 cache: 128K
CPU: After all inits, caps: bfebfbff 00000000 00000000 00000080 00004400 
00000000 00000000
Intel machine check architecture supported.
Intel machine check reporting enabled on CPU#0.
CPU0: Intel P4/Xeon Extended MCE MSRs (12) available
CPU0: Thermal monitoring enabled
CPU: Intel(R) Celeron(R) CPU 2.40GHz stepping 09
Checking 'hlt' instruction... OK.
ACPI: setting ELCR to 0200 (from 0c88)
.
.
.

Linux Debian testing, kernel 2.6.16-rc5

Thanks for reply a regards

Michal

Re: Dmesg is not showing whole boot list

[Peter Hagervall]

On Tue, Mar 14, 2006 at 09:01:27AM +0100, CIJOML wrote:
> Hello,
> 
> maybe this si a wrong list to ask, bug after boot, dmesg shows that few lines 
> at the beginning are missing.
> 
> Is there any option I can increase to get full dmesg?

Try increasing CONFIG_LOG_BUF_SHIFT and recompile. That's likely the
source of your problem.



	Peter Hagervall

Re: Dmesg is not showing whole boot list

[Phillip Susi]

Or look in your /var/log/kern.log file instead of asking dmesg.  dmesg 
just dumps the kernel ring buffer which is of finite size.  The entire 
contents should be logged to /var/log/kern.log.

Peter Hagervall wrote:
> On Tue, Mar 14, 2006 at 09:01:27AM +0100, CIJOML wrote:
>> Hello,
>>
>> maybe this si a wrong list to ask, bug after boot, dmesg shows that few lines 
>> at the beginning are missing.
>>
>> Is there any option I can increase to get full dmesg?
> 
> Try increasing CONFIG_LOG_BUF_SHIFT and recompile. That's likely the
> source of your problem.
> 
> 
> 
> 	Peter Hagervall
> 

Re: Dmesg is not showing whole boot list

[Gene Heskett]

On Tuesday 14 March 2006 10:05, Phillip Susi wrote:
>Or look in your /var/log/kern.log file instead of asking dmesg.  dmesg
>just dumps the kernel ring buffer which is of finite size.  The entire
>contents should be logged to /var/log/kern.log.

You've got to have /var checked and mounted to be able to do that log 
write, if the buffer overflows before that, then the head end of the 
dmesg dump to the /var/log/dmesg file is lost forever.

There is a line that can be changed, in xconfig or by hand, to control 
the memory allocated for this ring buffer.

Finally found it in the xconfig display, left panel line=kernel hacking, 
right panel its under kernel debugging and shows only if thats checked, 
double click on the line that says : kernel log buffer size and enter a 
one digit increment from whats there now, maybe 2, I have mine set for 
16.  Your default may be as low as 14, why I have NDI because 16k sure 
as heck isn't enough if something gets chatty.

>Peter Hagervall wrote:
>> On Tue, Mar 14, 2006 at 09:01:27AM +0100, CIJOML wrote:
>>> Hello,
>>>
>>> maybe this si a wrong list to ask, bug after boot, dmesg shows that
>>> few lines at the beginning are missing.
>>>
>>> Is there any option I can increase to get full dmesg?
>>
>> Try increasing CONFIG_LOG_BUF_SHIFT and recompile. That's likely the
>> source of your problem.
>>
>>
>>
>> 	Peter Hagervall
>
>-
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-- 
Cheers, Gene
People having trouble with vz bouncing email to me should add the word
'online' between the 'verizon', and the dot which bypasses vz's
stupid bounce rules.  I do use spamassassin too. :-)
Yahoo.com and AOL/TW attorneys please note, additions to the above
message by Gene Heskett are:
Copyright 2006 by Maurice Eugene Heskett, all rights reserved.

Re: Dmesg is not showing whole boot list

[Kyle Moffett]

On Mar 14, 2006, at 12:16:23, Gene Heskett wrote:
> On Tuesday 14 March 2006 10:05, Phillip Susi wrote:
>> Or look in your /var/log/kern.log file instead of asking dmesg.   
>> dmesg just dumps the kernel ring buffer which is of finite size.   
>> The entire contents should be logged to /var/log/kern.log.
>
> You've got to have /var checked and mounted to be able to do that  
> log write, if the buffer overflows before that, then the head end  
> of the dmesg dump to the /var/log/dmesg file is lost forever.
>
> There is a line that can be changed, in xconfig or by hand, to  
> control the memory allocated for this ring buffer.
>
> Finally found it in the xconfig display, left panel line=kernel  
> hacking, right panel its under kernel debugging and shows only if  
> thats checked, double click on the line that says : kernel log  
> buffer size and enter a one digit increment from whats there now,  
> maybe 2, I have mine set for 16.  Your default may be as low as 14,  
> why I have NDI because 16k sure as heck isn't enough if something  
> gets chatty.

To continue this point; on my desktop I have root/var/tmp/vicepa-on- 
LVM-on-RAID5, boot-on-RAID1, and swap-on-RAID1, so I would easily  
overflow the default SMP dmesg buffer size in messages well before  
syslogd/bootlogd got started.  I finally ended up having to increment  
the default by 3 in order to have the boot messages still available  
after booting.  It would be nice if we could quiet down some of the  
more excessively verbose kernel messages, there's a lot of mostly- 
irrelevant spew that chews up log buffer space.

Cheers,
Kyle Moffett

Re: Dmesg is not showing whole boot list

[Gene Heskett]

On Tuesday 14 March 2006 12:28, Kyle Moffett wrote:
>On Mar 14, 2006, at 12:16:23, Gene Heskett wrote:
>> On Tuesday 14 March 2006 10:05, Phillip Susi wrote:
>>> Or look in your /var/log/kern.log file instead of asking dmesg.
>>> dmesg just dumps the kernel ring buffer which is of finite size.
>>> The entire contents should be logged to /var/log/kern.log.
>>
>> You've got to have /var checked and mounted to be able to do that
>> log write, if the buffer overflows before that, then the head end
>> of the dmesg dump to the /var/log/dmesg file is lost forever.
>>
>> There is a line that can be changed, in xconfig or by hand, to
>> control the memory allocated for this ring buffer.
>>
>> Finally found it in the xconfig display, left panel line=kernel
>> hacking, right panel its under kernel debugging and shows only if
>> thats checked, double click on the line that says : kernel log
>> buffer size and enter a one digit increment from whats there now,
>> maybe 2, I have mine set for 16.  Your default may be as low as 14,
>> why I have NDI because 16k sure as heck isn't enough if something
>> gets chatty.
>
>To continue this point; on my desktop I have root/var/tmp/vicepa-on-
>LVM-on-RAID5, boot-on-RAID1, and swap-on-RAID1, so I would easily
>overflow the default SMP dmesg buffer size in messages well before
>syslogd/bootlogd got started.  I finally ended up having to increment
>the default by 3 in order to have the boot messages still available
>after booting.  It would be nice if we could quiet down some of the
>more excessively verbose kernel messages, there's a lot of mostly-
>irrelevant spew that chews up log buffer space.

I think thats somewhat true but then when you need that info for 
figureing out what didn't work, its priceless.  The only thing I'd 
stick a hot potato in is ACPI, its turned off in the config and still 
supplies about 5k of its mewling on boot.  But my /proc/interrupts says 
its not working, which is what counts so I can keep good time with 
ntpd.

>Cheers,
>Kyle Moffett

-- 
Cheers, Gene
People having trouble with vz bouncing email to me should add the word
'online' between the 'verizon', and the dot which bypasses vz's
stupid bounce rules.  I do use spamassassin too. :-)
Yahoo.com and AOL/TW attorneys please note, additions to the above
message by Gene Heskett are:
Copyright 2006 by Maurice Eugene Heskett, all rights reserved.

Re: Dmesg is not showing whole boot list

[CIJOML]

This helped. 

Thanks

Michal

Dne út 14. března 2006 09:38 jste napsal(a):
> On Tue, Mar 14, 2006 at 09:01:27AM +0100, CIJOML wrote:
> > Hello,
> >
> > maybe this si a wrong list to ask, bug after boot, dmesg shows that few
> > lines at the beginning are missing.
> >
> > Is there any option I can increase to get full dmesg?
>
> Try increasing CONFIG_LOG_BUF_SHIFT and recompile. That's likely the
> source of your problem.
>
>
>
> 	Peter Hagervall

Re: Dmesg is not showing whole boot list

[Randy.Dunlap]

On Wed, 15 Mar 2006 05:34:42 +0100 CIJOML wrote:

> This helped. 
> 
> Thanks
> 
> Michal

BTW, you don't have to recompile to get this.  You can also
add this to the kernel boot/command line:

	log_buf_len=n	Sets the size of the printk ring buffer, in bytes.
			Format: { n | nk | nM }
			n must be a power of two.  The default size
			is set in the kernel config file.


> Dne út 14. března 2006 09:38 jste napsal(a):
> > On Tue, Mar 14, 2006 at 09:01:27AM +0100, CIJOML wrote:
> > > Hello,
> > >
> > > maybe this si a wrong list to ask, bug after boot, dmesg shows that few
> > > lines at the beginning are missing.
> > >
> > > Is there any option I can increase to get full dmesg?
> >
> > Try increasing CONFIG_LOG_BUF_SHIFT and recompile. That's likely the
> > source of your problem.

---
~Randy