Re: [PATCH 1/5] Add functions producing system time given a backing counter value

On Wed, Jul 29, 2015 at 01:48:41PM +0200, Richard Cochran wrote:

On Wed, Jul 29, 2015 at 12:49:44PM +0200, Peter Zijlstra wrote:

quoted

This is still fuzzy, right? The hardware ART timestamp could be from
_before_ the NTP adjust; or the NTP adjust could happen while we do this
conversion and we'll take the retry loop.

In the original series, yes.
 

quoted

In both cases, the resulting value is computed using a different slope
than was in effect at the time of the stamp. With the end result being
slightly off from what it should be.

In Thomas' patch the get_ts() is meant to read fresh pairs of time
stamps from within the loop.

Ah, indeed, I missed that. Yes if that's possible we get it right.