Re: [PATCH] correct inconsistent ntp interval/tick_length usage

From: Roman Zippel
Date: Mon Jan 28 2008 - 23:02:38 EST


Hi,

On Mon, 28 Jan 2008, john stultz wrote:

> Regardless, current_tick_length() really is the base interval we're
> using in the error accumulation loop, so it seems the cleanest interface
> to use (just to avoid redundancy at least) when establishing the
> clocksource's interval length. Or do you not agree?

I see, what you need to use in timex.h for !CONFIG_NO_HZ is:

#define NTP_INTERVAL_LENGTH ((s64)LATCH * NSEC_PER_SEC) / (s64)CLOCK_TICK_RATE)

this calculates the base length of a clock tick in nsec.

current_tick_length() would only work during boot. If you switch clocks
later, it would include random adjustments specific to the old clock.

bye, Roman
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