Re: [PATCH] printk: Print cpuid along with the timestamp with CONFIG_PRINTK_TIME

[Marcin Slusarz <marcin.slusarz@gmail.com>]

On Thu, Sep 18, 2008 at 05:35:09PM -0700, Ravikiran G Thirumalai wrote:
> On Thu, Sep 18, 2008 at 12:51:23PM -0700, Andrew Morton wrote:
> >On Thu, 18 Sep 2008 12:37:20 -0700
> >Ravikiran G Thirumalai <kiran@scalex86.org> wrote:
> >> 
> >> Signed-off-by: Ravikiran Thirumalai <kiran@scalex86.org>
> >> 
> >> Index: linux-git/kernel/printk.c
> >> ===================================================================
> >> --- linux-git.orig/kernel/printk.c	2008-09-16 15:37:48.000000000 -0700
> >> +++ linux-git/kernel/printk.c	2008-09-18 12:27:10.489662938 -0700
> >> @@ -739,9 +739,10 @@ asmlinkage int vprintk(const char *fmt, 
> >>  
> >>  				t = cpu_clock(printk_cpu);
> >>  				nanosec_rem = do_div(t, 1000000000);
> >> -				tlen = sprintf(tbuf, "[%5lu.%06lu] ",
> >> +				tlen = sprintf(tbuf, "[%5lu.%06lu:%d] ",
> >>  						(unsigned long) t,
> >> -						nanosec_rem / 1000);
> >> +						nanosec_rem / 1000,
> >> +						printk_cpu);
> >>  
> >>  				for (tp = tbuf; tp < tbuf + tlen; tp++)
> >>  					emit_log_char(*tp);
> >
> >
> >Your patch illogically ties the cpu-id-printing feature to the
> >printk.time feature.  I guess that's liveable with, but
> >Documentation/kernel-parameters.txt should be updated.
> >
> 
> Didn't realize Documentation/kernel-parameters.txt had reference and even a
> runtime parameter to control this!  I always enabled CONFIG_PRINTK_TIME
> to get timestamps. Here's an updated patch.
> 
> As for the cpuid with the timestamp, the timestamp that is being
> is  the printed the cpu's time stamp.

Do we really need this information on UP kernels?
Why don't you add another option for this feature?

Marcin