Re: [patch 00/46] High resolution timer / dynamic tick update

Andrew Morton
2007-01-24T02:25:05Z

On Tue, 23 Jan 2007 18:16:31 -0800
Daniel Walker <dwalker@mvista.com> wrote:

> On Tue, 2007-01-23 at 22:00 +0000, Thomas Gleixner wrote:
> > - Provide a generic way to verify clocksources. TSC needs
> > verification due to broken hardware and BIOS implementations. The
> > previous attempt to allow TSC usage for high resolution and/or
> > dynamic ticks only in combination with the PM-Timer made hardwired
> > assumptions, which are ugly to maintain. The new verification code
> > solves this by chosing the best available clocksource for
> > verification and handles the usability check for highres / dynamic
> > ticks. This makes TSC code agnostic of other hardware available in
> > the system.
>
>
> There appears to be some fairly clear duplication between my clocksource
> tree and this release of high resolution timers. Not to mention that we
> both submitted our tree's to Andrew within days .
>
> To lessen Andrews burden it would be wise to integrate the two trees
> prior to anything going into -mm .. It makes sense to eliminate this
> kind of duplication since it just results in wasted effort. With the
> benefit that the merge would likely result in a stronger patch set over
> all.
>

There's also the question of testing status. We know that the dynticks
patches in -mm mostly work. Now that they appear to have been largely respun,
we don't know that any more. Then if we go adding more stuff on top, problem
identification becomes harder.

I thought that dynticks/hrtimers was a done thing: in fact $certain_people wanted
them in 2.6.20. The late-breaking rip-up-and-rewrite was rather unwelcome. But
I haven't got onto reading the patchset yet.