Re: powerpc64 head -r344018 stuck sleeping problems: th->th_scale * tc_delta(th) overflows unsigned 64 bits sometimes [patched failed]
Michael Tuexen <[email protected]>
| Newsgroups | gmane.os.freebsd.devel.ppc,gmane.os.freebsd.devel.hackers |
|---|---|
| Message-ID | <[email protected]> |
> On 3. Apr 2019, at 09:00, Konstantin Belousov <[email protected]> wrote: > > On Wed, Apr 03, 2019 at 12:27:32AM +0200, Michael Tuexen wrote: >>> On 24. Mar 2019, at 12:01, Konstantin Belousov <[email protected]> wrote: >>> >>> On Sat, Mar 09, 2019 at 06:00:14PM +1100, Bruce Evans wrote: >>>> I more strongly disclike (sic) the more complete merge. The central APIs >>>> have even more parameters and reduced type safety to describe objects as >>>> (offset, size) pairs. >>> I changed the patch to be type-safe. Now I like it even more. It provides >>> 1. internal >>> 2. concise >>> 3. type-safe >>> API to fetch data from timehands. The implementation needs to be read >>> only once. >> Hi, >> >> I'm a bit lost... I think this started to fix a problem on G5 PowerMacs. >> Do you think this patch solves the problem. Should this be tested? >> Or is this still work in progress or a general improvement not necessary >> fixing the problem on G5 PowerMacs? > > It started from a report of issues on G5. The specific issues are > bugs on G5, and the posted patches do not fix them. From what I see, > the timecounter values were wrapped. This is genuine ppc or G5 issue. Thanks a lot for the clarification. Best regards Michael > > The patch fixes time keeping subsystem reaction to the already > bad situation, by correctly handling overflow in calculations. This > overflow can occur in more reasonable setups as well, e.g. if ddb was > activated and interrupts were stopped for prolonged period, even on x86. > > In addition, my version of the patch reorganizes the code and removes > excessive copies of the most delicate loops in lock-less readers. This > chunk can be split from the overflow part, but it is not completely > trivial. _______________________________________________ [email protected] mailing list https://lists.freebsd.org/mailman/listinfo/freebsd-ppc To unsubscribe, send any mail to "[email protected]"