Messages in this thread | | | Date | Thu, 4 Feb 2010 14:05:22 +0300 | From | Alexander Gordeev <> | Subject | Re: [PATCH 2/5] pps: capture MONOTONIC_RAW timestamps as well |
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В Wed, 03 Feb 2010 14:26:16 -0800 john stultz <johnstul@us.ibm.com> пишет:
> On Wed, 2010-02-03 at 23:56 +0300, Alexander Gordeev wrote: > > MONOTONIC_RAW clock timestamps are ideally suited for frequency > > calculation and also fit well into the original NTP hardpps design. > > Now phase and frequency can be adjusted separately: the former > > based on REALTIME clock and the latter based on MONOTONIC_RAW clock. > > A new function getnstime_raw_and_real is added to timekeeping > > subsystem to capture both timestamps at the same time and > > atomically. > > Hrmm. So while I understand the need for it, the > getnstime_raw_and_real() makes me cringe a little. Part of the issue > is that there are multiple CLOCK_IDs and the current interface allows > for accesses to only one at a time. There's a similar hack in the > hrtimer code to get the CLOCK_REALTIME and CLOCK_MONOTONIC values at > the same time. Next I worry that folks will want a > getnstime_mono_and_raw() or a getnstime_real_mono_and_raw(), then a > getnstime_real_and_realcoarse(), etc.. > > I'm almost thinking the way to handle this would be a better > abstraction, like a get_two_times(CLOCKID, timepsec*, CLOCKID, > timespec*). But that might need some further discussion. Anyone else > have thoughts here?
Agreed with you completely. I don't like the approach but failed to invent anything better.
> So yea not opposed to this patch, but maybe try to avoid exporting the > symbol, so modules don't end up using it and we can change it fairly > easily later.
Well, I'd like to, but how? getnstime_raw_and_real() is used in module added in one of the next commits.
-- Alexander [unhandled content-type:application/pgp-signature] | |