Re: CONFIG_PRINTK_TIME and initial value for jiffies?

[Sergei Shtylyov <sshtylyov@ru.mvista.com>]

Hello.

Clem Taylor wrote:
> I just switched to 2.6.16.16 from 2.6.14 on a Au1550. I enabled
> CONFIG_PRINTK_TIME, and for some reason jiffies doesn't start out near
> zero like it does on x86. The first printk() always seems to have a
> time of 4284667.296000.
> jiffies_64 and wall_jiffies gets initialized to INITIAL_JIFFIES, but
> I'm not sure where jiffies is initialized. INITIAL_JIFFIES is -300*HZ
> (with some weird casting)
> The first line on the 2.6.16.16 Au1550 box is:
> [4294667.296000] Linux version 2.6.16.16 (ctaylor@gort) (gcc version
> 4.1.0) #4 Mon May 15 13:06:37 EDT 2006
   Well, this number looks a lot like -300 secs printed as unsigned --
given the fact that jiffies are unsigned, there's no surprise...
   My first guess is that TSC code used on x86 corrected jiffies_64 before 
they got used by sched_clock(). Probably a bogus guess because TSC should have 
been used by sched_clock() itsefl then...
MBR, Sergei