On Thu, 2010-12-02 at 01:18 +0000, Jamie Lokier wrote: > Valdis.Kletnieks@xxxxxx wrote: > > On Wed, 01 Dec 2010 10:43:59 GMT, Jamie Lokier said: > > > > > So maybe CLOCK_MONOTONIC should be changed to include elapsed time > > > during suspend/resume, and CLOCK_MONOTONIC_RAW could remain as it is, > > > for programs that want that? > > > > Wouldn't that be an API break for programs that are expecting the current > > behavior of CLOCK_MONOTONIC? Yes, there should be a way to request either of > > them - but if there's only one way now, it should continue to act the current > > way, and the added way is the second option. > > I don't know. Can you think of any program which would break if > suspend/resume's clocks behaved like ordinary task scheduling - when a > task doesn't run for a long time because of scheduling decisions? > Hmm, I guess some realtime apps might like to know. Like I mentioned earlier, CLOCK_MONOTONIC_RAW and CLOCK_MONOTONIC are tightly tied, so anything using CLOCK_MONOTONIC_RAW would break. It might be possible to change both, but I still think such a change would be bad. > Currently CLOCK_MONOTONIC jumps forwards by 4 seconds on > suspend/resume anyway (as seen by userspace), on my x86 laptop running > 2.6.37-rc3. So it does already jump a bit... So just to clarify here, by this do you mean that there's ~4 seconds delay between the resume event and when userland apps start to run (or possibly some of that accumulating between the app freeze and the timekeeping suspend) ? Or are you seeing CLOCK_MONOTONIC jump 4 seconds out of sync with CLOCK_REALTIME? It should be the delta between CLOCK_MONOTONIC and CLOCK_REALTIME prior to suspend should be that same delta + suspend time after resume. If that's not the case, something may be broken. thanks -john -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
