Date: Sun, 19 Jan 2020 17:24:28 -0600 From: Jason Bacon <bacon4000@gmail.com> To: freebsd-ppc@freebsd.org Subject: Re: G5 Quad Fans full speed after 1 min Message-ID: <08867d39-807a-494b-9ea5-d29d483e9c29@gmail.com> In-Reply-To: <21533290-667C-472E-89F7-D1E7DE773193@yahoo.com> References: <CAGSRtz76TC44UiECMepLAZjXE=H33sg4OFLJpmZpNCSEwE=ETQ@mail.gmail.com> <21533290-667C-472E-89F7-D1E7DE773193@yahoo.com>
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On 2020-01-19 05:13, Mark Millard via freebsd-ppc wrote: > On 2020-Jan-19, at 00:38, Francis Little <oggy at farscape.co.uk> wrote= : > >> Hi, >> >> My G5 Quad is running current from a few days ago, but this issue has = been >> happening for a long time. >> >> After about 1 min of uptime, the fans go full speed. >> >> As soon as I query anything like CPU temp or fan rpm with sysctl, the = fans >> return to a normal speed. >> >> 1 min later the fans go full speed again. >> >> I've been working round this for some time with a cron job that runs s= ysctl >> with one of the cpu temp sensors to calm the system. > QUOTING an old message: > The mftb figures on the various cores can be so far apart that > threads can end-up stuck sleeping, such as syncr, pmac_thermal, > and buf*deamon* threads. (This can really mess things up by > not updating the storage correctly.) Such is still true of the > ELFv2 context. > > (Most folks notice this via shutdown timeouts and the fans > going fast unnecessarily. But it is involved earlier as well.) > END QUOTE > > Nothing in the boot sequence is forcing the CPUs/Cores to > see any particular time relationship to each other and on > the multi-socket PowerMacs it can vary widely (G4 and G5). > Sometimes it will happen to end up okay, other times not. > > (I've no access to a single-socket, multi-core PowerMac, > so I just do not know for that kind of context.) > > I run with patched boot-code that has cross-cpu/core time > observations and adjustments to non-bsp time to see the > bsp time as between the start and end of a round trip to > the bsp from each non-bsp to get the bsp's time. It is > based on the mid-point of the start and end times for > the non-bsp's round trip vs. the bsp's returned time. > With at most 4 cores, each non-bsp is done in sequence. > The code only does this on PowerMacs, having no access > to other types of PowerPC examples to test. > > I've not seen this type of problem since mid 2019-May on > any of: > > 1 G5 with 2 sockets, 1 core each > 2 G5's, 2 sockets, 2 cores each > 2 G4's, 2 sockets, 1 core each > > (The mid-May time frame is when I adjusted the code to > deal with the faster time increment on the slower > 32-bit processors for the model that I have access to. > I had to be more careful to avoid biasing the approximate > symmetry to be less symmetric. On the G5's its been > longer since I've seen this problem, based on earlier > source code.) > > Unfortunately the "lab" the machines are in is powered > down currently. > > FYI: Prior to this technique, I had a pure hack that > was observed to avoid the problem. But it changed code > used all the time --code that I did not want to have > any hack's in if I could avoid it. > > FYI: I also run with other PowerMac related patches. > Generally this mftb() time adjustment is one of the > newest patches, possibly the newest. So my test > context may be biased by the other patches. > >> If I boot to OS X 10.5 and load the system, the fans are stable. > I've not done any investigation of the issue for the > older contexts. But, if I remember right, I did see > the problem on occasion back in that time frame. > >> Does anyone else get this? > My understanding is everyone booting a fairly modern > standard FreeBSD gets this sometimes for the kind of > context that you specified. (I'm not sure of the > variability if the frequency of the problem happening > for that kind of context.) > > I certainly saw it before I investigated avoiding it. > > =3D=3D=3D > Mark Millard > marklmi at yahoo.com > ( dsl-only.net went > away in early 2018-Mar) > > _______________________________________________ > freebsd-ppc@freebsd.org mailing list > https://lists.freebsd.org/mailman/listinfo/freebsd-ppc > To unsubscribe, send any mail to "freebsd-ppc-unsubscribe@freebsd.org" On my dual CPU PowerMac G5, this issue happens for 80 - 90% of boots. I'd love to test a patch if one is available.=C2=A0 Cutting the speed in = half=20 would be problematic for testing large ports. Thanks, =C2=A0=C2=A0=C2=A0 JB --=20 Earth is a beta site.
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