Date: Sat, 16 Mar 2013 15:59:29 -0400 From: Jim Ohlstein <jim@ohlste.in> To: freebsd-stable@FreeBSD.org Cc: jdc@koitsu.org, rpaulo@FreeBSD.org, zkolic@sbb.rs, Don Lewis <truckman@FreeBSD.org>, nork@FreeBSD.org, jkim@FreeBSD.org Subject: Re: amdtemp does not find my CPU. Message-ID: <5144CF21.5060900@ohlste.in> In-Reply-To: <201303161824.r2GIO53r006067@gw.catspoiler.org> References: <201303161824.r2GIO53r006067@gw.catspoiler.org>
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On 3/16/13 2:24 PM, Don Lewis wrote: > On 16 Mar, Jim Ohlstein wrote: [snip] >>> On Fri, Mar 15, 2013 at 03:16:19PM -0400, Jim Ohlstein wrote: [snip] >> >> Note the big change between lines 34 and 35. > > My FX-4100 behaves the same way. I noticed it because on an idle system > sysctl -a | grep amdtemp > would read consistently higher than > sysctl dev.amdtemp > > I think the thermal sensor in this AMD CPU family has a much faster > response time so that it is more sensitive to temperature changes caused > by CPU load over the short term. Going from idle to 100% CPU load for > even 0.1 seconds and then back to idle is likely to change the die > temperature a lot, but will probably only have a negligible effect on > the heat sink temperature. The faster response time may be needed to > support AMD Turbo CORE. > That's very possible. This is not an idle system so I cannot really test that out without taking it offline. My results on that comparison are therefore perhaps not valid. However, I don't see much difference. See http://pastebin.com/Rk0sbhhL. When I stress the CPU the temps simply stay high without any fluctuation, but do show those rapid rises both before and after. This supports your explanation. Of course this still does not explain the observed differences between the two modules on the other machine. -- Jim Ohlstein
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