Re: [PATCH] support printk-times by fixing sched_clock to be callable in early boot

[tony@atomide.com]

Hi,

* Tim Bird <tim.bird@am.sony.com> [060823 21:37]:
> Hi all,
> 
> This patch has been sitting in my 'to-submit' queue for a long time.
> 
> Basically, you can't use the printk times feature on omap, because
> by default it calls sched_clock() before the timer is set up, which
> causes the machine to hang.  This simplistic fix makes sched_clock()
> return 0 until the clock has been properly initialized.
>  
> The overhead of the flag check is not big, but it's impact could
> be reduced by moving the test into a separate printk_clock()
> routine (which would front the sched_clock() function, and
> is only called by printk when printk timing is active.)
> Let me know if you would prefer that I rework this patch to
> use that approach instead.

Sorry for the long delay in replying. Let's rather implement
printk_clock() like you suggest as sched_clock is called quite a bit.
That should also allow us to remove the current hack
e4fb3a282725bc66dc63fd248e9d05e0396ddf95 in kernel/printk.c.

Regards,

Tony