[coreboot] printing TSC in printk
c-d.hailfinger.devel.2006 at gmx.net
Sun Feb 10 16:41:25 CET 2008
On 10.02.2008 15:03, Peter Stuge wrote:
> On Sat, Feb 09, 2008 at 12:50:28PM -0800, ron minnich wrote:
>> Define an option
> This is good. Linux has the same option.
>> What it does: each time printk would print a newline, it will
>> instead print this:
>> (16 hex digits of TSC)\n
> Pro: Every line has time
> Con: Time is last on the line
Insertion at start for every printk will work as well unless you use
multiple prinks to fill one line. That would be the Linux concept.
>> Define a new format letter, T, such that %T as a format means
> Pro: Time can be first on line
> Con: We need to add it manually.
> Doing it like Linux would need a static variable near printk() to
> keep \n state. :\
I have a patch which gives us as many static variable as we want.
>> first option allows comprehensive timing, but it will slow things
>> down a bit.
> This must be optional though.
>> Second option allows us to completely tailor the printing of
>> time, but you have to explicitly add %T when you want time
> I think it is important that the time always is printed at the same
> position in a line, but manually having to add %T to every printk is
> Maybe the answer is a macro wrapper around printk() (why is it called
Please no macros.
> print_k_ by the way, we are not the kernel) which is defined
> differently depending on the config option.
> If the option is set, the macro always prepends "%T " to the format
Now I see what you're trying to do. Nice idea. The "%T" support patch
(see my other mail in this thread) could be used as a basis for this idea.
More information about the coreboot