Re: [patch] sched: make cpu_clock() not use the rq clock

[Eric St-Laurent]

On Thu, 2007-26-07 at 11:00 +0200, Ingo Molnar wrote:
> Subject: sched: make cpu_clock() not use the rq clock
> From: Ingo Molnar <mingo@xxxxxxx>
> 
> it is enough to disable interrupts to get the precise rq-clock
> of the local CPU.

Hi Ingo,

Those new fast nanoseconds resolution clock APIs are nice but it seems
to me that their naming and _where_ they are implemented in the tree is
a little odd, IMO.

We have:

1. sched_clock() is in kernel/sched.c (weak implementation)
2. sched_clock() is in arch/i386/kernel/tsc.c (architecture override)
3. rq_clock() is in kernel/sched.c
4. cpu_clock() is in kernel/sched.c

I would suggest:

1. rename sched_clock() (remove sched_ as it's not sched specific
anymore) and place it in kernel/time/...
2. rename the architecture specific version of it too 

This first function is the basic fast ns clock

3. base your rq_clock() on cpu_clock() (#4) or use the later directly.

This is local to sched.c

4. move cpu_clock() in kernel/time/...

This the per-cpu monotonic version.


See my point? Base the scheduler clock from a general kernel API, not
the other way around.

Just a suggestion.


Best regards,

- Eric


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