Re: Re: printk performance logging without syslogd for router

Re: Re: printk performance logging without syslogd for router

[william fitzgerald]

---- Begin Original Message ----
 From: Peter Wächtler <pwaechtler@loewe-komp.de>
Sent: Tue, 13 Nov 2001 13:15:45 +0100
To: william fitzgerald
<william.fitzgerald3@beer.com>
CC: linux-kernel@vger.kernel.org
Subject: Re: printk performance logging without
syslogd for router


william fitzgerald wrote:
> 
> hi all,
> 
> (perforamnce logging of network stack through a
> linux router)
> 
> the main question:
> 
> is there a way i can buffer or record  the
printk
> statements and print them to disk  after my
> packets have gone through the router?
> 

there is an option in syslogd to prevent
immediatly
writing to the logfile:

prefix the log with a dash:

kern.*	-/var/log/kernelmessages

---- End Original Message ----

what does klogd do?

i thought klogd writes to disk if you turn off
syslogd.that way you only have one over head.




Beer Mail, brought to you by your friends at beer.com.

Re: printk performance logging without syslogd for router

[Peter Wächtler]

william fitzgerald wrote:
> 
> ---- Begin Original Message ----
>  From: Peter Wächtler <pwaechtler@loewe-komp.de>
> Sent: Tue, 13 Nov 2001 13:15:45 +0100
> To: william fitzgerald
> <william.fitzgerald3@beer.com>
> CC: linux-kernel@vger.kernel.org
> Subject: Re: printk performance logging without
> syslogd for router
> 
> william fitzgerald wrote:
> >
> > hi all,
> >
> > (perforamnce logging of network stack through a
> > linux router)
> >
> > the main question:
> >
> > is there a way i can buffer or record  the
> printk
> > statements and print them to disk  after my
> > packets have gone through the router?
> >
> 
> there is an option in syslogd to prevent
> immediatly
> writing to the logfile:
> 
> prefix the log with a dash:
> 
> kern.*  -/var/log/kernelmessages
> 
> ---- End Original Message ----
> 
> what does klogd do?
> 
> i thought klogd writes to disk if you turn off
> syslogd.that way you only have one over head.
> 

OK, normally klogd pushes the messages to syslog.
Then syslogd decides where and how to write to disk.

If you use "klogd -f /tmp/logfile" I don't know how
to prevent immediate write()s to disk. The source code
of klogd will tell you :-)