Re: + clocksource-add-generic-sched_clock.patch added to -mm tree

[Daniel Walker <dwalker@mvista.com>]

On Sun, 2006-10-08 at 23:41 +0200, Thomas Gleixner wrote:
> On Sun, 2006-10-08 at 14:33 -0700, Daniel Walker wrote:
> > On Sun, 2006-10-08 at 23:21 +0200, Thomas Gleixner wrote:
> > > On Sun, 2006-10-08 at 14:15 -0700, Daniel Walker wrote:
> > > > On Sun, 2006-10-08 at 20:45 +0200, Thomas Gleixner wrote:
> > > > 
> > > > > > I'm not moving the kernel/timer.c clocksource user back into
> > > > > > kernel/time/clocksource.c . That code completely belongs with the
> > > > > > generic time of day changes. The code is directly coupled, and in fact
> > > > > > it improves the timekeeping clock switching code to have it that way.
> > > > > 
> > > > > I don't see any reason, why it must be added to timer.c. You can achieve
> > > > > the same result with calling the code outside, except that the compiler
> > > > > might miss some inline optimization. The switch clock code is not a
> > > > > hotpath and so it does not matter whether it is called here or there.
> > > > 
> > > > It wouldn't be as clean to integrate the two. The hotpath is improved
> > > > (which is what I was referring too above.)
> > > 
> > > Sorry, where is which hotpath improved ?
> > 
> > The hotpath in update_wall_time() kernel/timer.c which involves clock
> > switching.
> 
> And why the heck does this require to move _clocksource_ related code
> including sysfs hackery into timer.c ? Your improvement works with
> extern code as well.

There are no clocksource internals added by me. There is a exposed
clocksource API which is all that is used.

The design of the original clocksource interface was specific for
timekeeping. What I did was modified it to be used by more than just
timekeeping.

If I add tons of externs there and cram all that into clocksource.c ,
that would just be a mess. Then we're tending back to the original
clocksource design when it's designed just for time keeping.

Daniel

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