Re: [RFC][PATCH] new timeofday core subsystem (v. A2)

[john stultz]

On Mon, 2005-01-24 at 15:24 -0800, Christoph Lameter wrote:
> On Mon, 24 Jan 2005, john stultz wrote:
> > +	/* convert to nanoseconds */
> > +	ns_offset = cyc2ns(timesource, delta, NULL);
> > +
> > +	/* apply the NTP scaling */
> > +	ns_offset = ntp_scale(ns_offset);
> 
> The monotonic clock is the time base for the gettime and gettimeofday
> functions. This means ntp_scale() is called every time that the kernel or
> an application access time.
> 
> As pointed out before this will dramatically worsen the performance
> compared to the current code base.
> 
> ntp_scale() also will make it difficult to implement optimized arch
> specific version of function for timer access.
> 
> The fastcalls would have to be disabled on ia64 to make this work. Its
> likely extremely difficult to implement a fastcall if it involves
> ntp_scale().


Yep, performance is a big concern. Re-working ntp_scale() is still on my
TODO list. I just didn't get to it in this release. 

Patches are always welcome.  :)

thanks for the feedback!
-john

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