Re: 2.6.14-rt13
From: Lee Revell
Date: Sat Nov 19 2005 - 13:36:27 EST
On Sat, 2005-11-19 at 08:45 +0100, Vojtech Pavlik wrote:
> On Fri, Nov 18, 2005 at 06:28:24PM -0800, George Anzinger wrote:
> > Finding it is another matter. It does not have a fixed address (i.e.
> > it differs from machine to machine, but is constant on any given
> > machine). The boot code roots it out of an info block put in memory
> > by the BIOS. I suppose one could put a printk in the boot code to
> > disclose it...
>
> There is really no reason to do that, since the time to read it (~1200
> ns) is much less than the time to enter the kernel (less than 200 ns),
> so gettimeofday() is definitely easier to use and also doesn't overflow.
>
Thanks very much, you have answered my question. We would prefer
gettimeofday() anyway for portability, so if the plan is to make it
faster then we can deal with losing the TSC.
Lee
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