Messages in this thread | | | Date | Wed, 8 Dec 2004 15:47:21 -0800 (PST) | From | Christoph Lameter <> | Subject | Re: [RFC] New timeofday proposal (v.A1) |
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On Wed, 8 Dec 2004, George Anzinger wrote:
> Right. We seem to be doing ok now by just adjusting things at tick time and > using the "normal" interpolation between ticks. > > As for the math, the current code keeps a running "remainder" which is the > amount of the correction that was finer than the clock resolution (i.e. less > than a nano second) and rolls this in on the next tick. This gives resolution > out to several bits to the right of the nano second. And I think this is all > done with 32 bit math (if memory serves).
That is probably the i386 version with which I am not familiar. The time interpolator logic (IA64 and SPARC64) does fine with a scaled 64 bit factor without a remainder. The factor may be used to express fractions of nanoseconds.
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