Date: Tue, 20 Jan 2015 00:01:55 -0800 From: Mark Millard <markmi@dsl-only.net> To: Justin Hibbits <chmeeedalf@gmail.com> Cc: FreeBSD PowerPC ML <freebsd-ppc@freebsd.org> Subject: Re: PowerMac G5 quad-core, CPU A1 DIODE TEMP: 90.8 C (for example): How to handle? [Mac OS X behavior] Message-ID: <8C1E55BF-199C-43F0-8583-5C5ADCFB4214@dsl-only.net> In-Reply-To: <818E5DB8-89F3-402F-BCCB-F693C45F7427@dsl-only.net> References: <42CF1E40-5BD5-4B00-86E9-C62AEB9B8B93@dsl-only.net> <15A6D627-9DC7-48AF-B133-94980AFCE46A@dsl-only.net> <20150115231129.1b28c8d0@zhabar.attlocal.net> <0631235D-A505-4C37-87D7-6F46A14552AB@dsl-only.net> <20150116233145.6708cc6f@zhabar.attlocal.net> <31331F84-63CC-48B7-81B5-E70A22E88CB7@dsl-only.net> <604BAA0A-FD15-4310-88B2-DFEE9988D1EB@dsl-only.net> <20150117080916.3e321a4f@zhabar.attlocal.net> <CAJ-Vmo=0-tzB0U2evzU9XNE6oQU-7_WnqmE%2B9pHWnvRTpkh-Tg@mail.gmail.com> <42358897-0AC2-4B35-BE01-1D4EB2CC2F47@dsl-only.net> <4B8426E1-B0C8-430E-BA9F-EBBF2B1B935E@dsl-only.net> <592299C1-C92D-4CB3-8C4A-DB12FF7D102B@dsl-only.net> <8E81058D-DFF8-4C54-8FA2-1202CC03081D@dsl-only.net> <CAHSQbTAmhdPHi7ts62n_pVQekE8ZRjY53zYubOu%2BoryGo7XFfQ@mail.gmail.com> <818E5DB8-89F3-402F-BCCB-F693C45F7427@dsl-only.net>
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In addition to the below notes that I sent to Justin and Nathan I =
installed the Processors system preference pane (from CHUD 4.6.2) and =
did an experiment with turning off and on "Allow Nap" under Mac OS X =
10.5.8 on the problematical G5 quad-core. I'll note that the whole time =
Mac OS X was keeping the RPM's near maximums so those are not much of a =
parameter set for this note.
With Allow Nap disabled the result for idle-conditions (well, =
Temperature Monitor running and the configuration's normal background =
activity going) was: the temperature gradually increased overall over =
2hr+ and then started the temperature oscillation pattern once it =
reached something around around 88C (for the same core as before). No =
benchmarks or other loads added.
Reenabling Allow Nap lead to the temperature dropping and staying down =
(compared to reaching 88C). (This matches earlier results were Allow Nap =
was implicitly enabled and so idle-conditions did not get to such high =
temperatures.)
Earlier activity reports establish that Allow Nap is not sufficient to =
keep the processors/cores cool when they are under load (with the high =
RPM's always involved).
=3D=3D=3D
Mark Millard
markmi at dsl-only.net
On 2015-Jan-17, at 10:56 PM, Mark Millard <markmi at dsl-only.net> =
wrote:
Hi. [The mail list will not get the pictures Justin and Nathan get with =
this.]
Mac OS X 10.5.8 has the pump and fans going nearly full tilt at idle =
once the cores have been warmed up for the problematical G5 quad core:
CPU A Core 1 56=C2=B0C
CPU A Core 2 65=C2=B0C
CPU B Core 1 44=C2=B0C
CPU B Core 2 44=C2=B0C
CPU A Intake 3104rpm
CPU B Intake 3104rpm
CPU A Exhaust 3200rpm
CPU B Exhaust 3200rpm
CPU A Pump 3600rpm
And Mac OS X 10.5.8 does not prevent the temperature rise. Mac OS X just =
does more to cool things down temporarily once critical temperatures =
happen, trading performance silently by having some idle time. Having =
FreeBSD be more like the above for the lower temperatures would still =
overheat before "make -j 8 buildworld buildkernel" would finish. (I =
think Justin's various RPM changes are great improvements to PowerPC =
FreeBSD but the problematical G5 quad core is just too defective to =
reasonably work around: I doubt that FreeBSD would want the silent =
performance tradeoff the later plots for Mac OS X indicate.)
By contrast the good G5 quad core is more like what one would expect =
when booted from the exact same Firewire 800 Mac OS X 10.5.8 disk (and =
warmed up):
CPU A Core 1 42=C2=B0C
CPU A Core 2 43=C2=B0C
CPU B Core 1 46=C2=B0C
CPU B Core 2 48=C2=B0C
CPU A Intake 970rpm
CPU B Intake 970rpm
CPU A Exhaust 1000rpm
CPU B Exhaust 1000rpm
CPU A Pump 1250rpm
[Past this point in these notes is likely of no interest from the mail =
list but may be for Justin and possibly even for Nathan.]
The later picture for (A) below shows the high temperatures reached for =
a good G5 quad core context.
I've collected Temperature Monitor data from Mac OS X for both a good G5 =
quad core and for the problematical one (for running 6 variants of the =
HINT benchmark at once). The information is in the form of screen shots =
of its temperature graphs. I've included:
A) GoodG5QuadCoreTemps6HINTs.jpg to show the stages (0) warmup, (1) 6 =
variants of HINT going at once, (2) cool down after stopping those 6 =
variants for the good G5 quad core. (Each HINT has some input that I =
type so very beginning of the start up is not smooth: idle for a bit =
after being busy for a bit.)
B) BadG5QuadCoreTemps6HINTs.jpg for the same warmup to cool down =
coverage but for the bad G5 quad core. But the high-temperature time =
frame is not sampled fast enough to show its structure correctly. There =
are lots of other differences compared to (A).
For the bad G5 quad core I've also included some short-term graphs that =
sampled fast enough to give some structure for the high temperature time =
frame...
C) BadG5QuadCoreTemps6HINTsStart.jpg showing the starting of the 6 HINTs =
and just after.
D) BadG5QuadCoreTemps6HINTsBeforeStop.jpg showing how the frequency and =
structure of the oscillations had changed by the time I was going to =
stop the 6 HINTs. This shows that some of the oscillation structure that =
I reported earlier eventually goes away and that the oscillation gets =
faster than what it starts out as --something I'd not reported before.
E) BadG5QuadCoreTemps6HINTsCooldown.jpg showing the cool down detail =
after I stopped the 6 HINTs. (Compare the beginning of this cooling with =
the oscillation cooling?)
=46rom all this I get that the problematical G5 quad core is definitely =
defective but Mac OS X 10.5.8 goes out of its way to keep operating =
anyway, trading off other things to make that happen. Other contexts =
might not want those same tradeoffs.
=3D=3D=3D
Mark Millard
markmi at dsl-only.net
On 2015-Jan-17, at 09:36 PM, Justin Hibbits <chmeeedalf at gmail.com> =
wrote:
I noticed on my quad running OS X spins up the fans all the way down at =
55C. Perhaps you can try that, set the initial multiplier to 300 or =
more. I can add a sysctl to change the multiplier, if that would help =
people.
-Justin
=
<GoodG5QuadCoreTemps6HINTs.jpeg><BadG5QuadCoreTemps6HINTs.jpeg><BadG5QuadC=
oreTemps6HINTsStart.jpeg><BadG5QuadCoreTemps6HINTsBeforeStop.jpeg><BadG5Qu=
adCoreTemps6HINTsCooldown.jpeg>
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