lkml.org 
[lkml]   [2009]   [Jul]   [23]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [RFC][patch 1/5] move clock source related code to clocksource.c
On Wed, 22 Jul 2009 17:28:20 -0700
john stultz <johnstul@us.ibm.com> wrote:

> Hey Martin,
> So here's a really quick swipe at breaking apart the clocksource struct
> into a clocksource only portion and a timekeeping portion.
>
> Caveats:
> 1) This doesn't completely build. The core bits do, but there's still a
> few left-over issues (see following caveats). Its just here to give you
> an idea of what I'm thinking about. I'd of course break it up into more
> manageable chunks before submitting it.
>
> 2) Structure names aren't too great right now. Not sure timeclock is
> what I want to use, probably system_time or something. Will find/replace
> before the next revision is sent out.
>
> 3) I still need to unify the clocksource and cyclecounter structures, as
> they're basically redundant now.
>
> 4) I still need to fix the update_vsyscall code (shouldn't be hard, I
> didn't want to run through arch code yet).
>
> 5) The TSC clocksource uses cycles_last to avoid very slight skew issues
> (that otherwise would not be noticed). Not sure how to fix that if we're
> pulling cycles_last (which is purely timekeeping state) out of the
> clocksource. Will have to think of something.
>
>
> Other cleanups still out there in the distant future:
> 1) Once all arches are converted to GENERIC_TIME, we can remove the
> ifdefs, and cleanup a lot of the more complicated xtime struct
> manipulation. It will cleanup update_wall_time() nicely.
>
> 2) I have a logarithmic accumulation patch to update_wall_time that will
> remove the need for xtime_cache to be managed and updated. Just have to
> spend some additional time making sure its bugfree.
>
> 3) Once all arches are converted to using read_persistent_clock(), then
> the arch specific time initialization can be dropped. Removing the
> majority of direct xtime structure accesses.
>
> 4) Then once the remaining direct wall_to_monotonic and xtime accessors
> are moved to timekeeping.c we can make those both static and embed them
> into the core timekeeping structure.
>
>
> But let me know if this patch doesn't achieve most of the cleanup you
> wanted to see.

Cool, I'll have a look. What I can see right away is that a lot of the
changes I tried yesterday are contained in your patch as well.
But your patch is more radical, a lot more is (re-)moved from the
struct clocksource. That mult_orig goes aways is good :-)

--
blue skies,
Martin.

"Reality continues to ruin my life." - Calvin.



\
 
 \ /
  Last update: 2009-07-23 09:55    [W:0.167 / U:0.712 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site