Re: [RFC][PATCH] new timeofday arch specific hooks (v. A3)

[Benjamin Herrenschmidt <benh@kernel.crashing.org>]

On Fri, 2005-03-11 at 17:25 -0800, john stultz wrote:
> All,
> 	This patch implements the minimal architecture specific hooks to enable
> the new time of day subsystem code for i386, x86-64, ia64, ppc32 and
> ppc64. It applies on top of my linux-2.6.11_timeofday-core_A3 patch and
> with this patch applied, you can test the new time of day subsystem. 
> 
> Basically it configs in the NEWTOD code and cuts alot of code out of the
> build via #ifdefs. I know, I know, #ifdefs' are ugly and bad, and the
> final patch will just remove the old code. For now this allows us to be
> flexible and easily switch between the two implementations with a single
> define.
> 
> New in this version:
> o ppc32 arch code (by Darrick Wong. Many thanks to him for this code!)
> o ia64 arch code (by Max Asbock. Many thanks to him for this code!)
> o minor cleanups moving code between the arch and timesource patches
> 
> Items still on the TODO list:
> o s390 arch port (hey Martin: nudge, nudge :)
> o arch specific vsyscall/fsyscall interface
> o other arch ports (volunteers wanted!)

I'm not what the impact will be with the vDSO implementation of
gettimeofday which relies on the bits in systemcfg (tb_to_xs etc...).

Currently, the userland code uses the exact same bits as the kernel
code, and thus, we have a garantee of getting the same results from
both. Also, our "special" ppc_adjtimex will also update our offset and
scale factor (with appropriate barriers) in a way that applies to both
the kernel/syscall gettimeofday and the vDSO implementation. I'm not
sure this is still true with your patch.

I suppose I'll have to dig into the details sometime next week..

Ben