Re: [PATCH] init/main.c: Use ktime accessor function in initcall_debug code.

[Will Newton]

On Thu, Nov 20, 2008 at 5:39 PM, Tim Bird <tim.bird@xxxxxxxxxxx> wrote:
> Will Newton wrote:
>> The initcall_debug code access the tv64 member of ktime. This won't work
>> correctly for large deltas on platforms that don't use the scalar ktime
>> implementation.
>
> In principle I see no problem with this.  But as a matter of
> practice it may be overkill.

Possibly, but it makes the code clearer I think.

> How big does the delta have to be for this to be a problem?
> And how much overhead does ktime_to_ns() add?

Deltas over a second will be incorrect. I have serial8250_init taking
8 seconds at the moment, so that isn't unheard of.

On scalar ktime architectures it should be zero, on others a multiply
and an add (it's an inline). I wouldn't call it a fast path though.

>  -- Tim
>
> =============================
> Tim Bird
> Architecture Group Chair, CE Linux Forum
> Senior Staff Engineer, Sony Corporation of America
> =============================
>
>
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