Date: Wed, 15 Sep 2010 15:10:03 GMT From: Hannes <freebsd@soulrebel.in-berlin.de> To: freebsd-bugs@FreeBSD.org Subject: Re: kern/140361: [cpufreq] speed-stepping broken on PhenomII (acpi?) Message-ID: <201009151510.o8FFA3Pr046337@freefall.freebsd.org>
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The following reply was made to PR kern/140361; it has been noted by GNATS. From: Hannes <freebsd@soulrebel.in-berlin.de> To: "Bruce Cran" <bruce@cran.org.uk> Cc: bug-followup@FreeBSD.org Subject: Re: kern/140361: [cpufreq] speed-stepping broken on PhenomII (acpi?) Date: Wed, 15 Sep 2010 17:00:38 +0200 Hi Bruce, thanks for your reply. > Hannes, > > It looks like powerd is doing its job: the line "dev.cpu.0.freq: 800" > shows that your CPU is running at 800MHz which is far below its > maximum. By checking the value of dev.cpu.0.freq every so often you > should see it reduce when the system is idle and increase when doing > CPU-intensive work like running a build etc. No, the point is that dev.cpu.0.freq is NOT adjusting automatically. =20 That's what got me starting this whole report. In the above example I =20 set it manually to 800, which actually works (e.g. the power =20 consumption goes down), but it only works manually and powerd does not =20 regulate it up, even if I put 100% load on all cores. > The cx_usage lines (e.g. dev.cpu.0.cx_usage: 100.00% last 500us) are > just reporting the amount of time the CPU was in a certain power state. > Since your CPU doesn't support C2 and C3 all the time is spent in C1 - > hence the "100%". That's normal, and would only be less than 100% if > you had C2 or C3 and you'd set hw.acpi.cpu.cx_lowest. The CPU should have C2 or C3. > I don't think this is a bug in FreeBSD if you can confirm that the > dev.cpu.0.freq value is changing. If so, I'd like to close this PR. - on FreeBSD i386 dev.cpu.0.cx_usage adjusts automatically, I have est =20 devices and C2/C3-states - on FreeBSD amd64 nothing adjusts automatically, est doesnt attach =20 and I dont get states So unless there is some amd64-related vodoo you have to do that I =20 don't know of (these are my only amd64-machines I ever had), I am =20 pretty sure it's a bug. I don't have access to the machines the next two weeks but can provide =20 further info then. I would gladly test patches aswell, if they apply =20 to RELENG_8. I will also try to get hold of an i386 install again and =20 then provide diffs of dmesg and sysctls. Thanks you very much for your help! Regards, Hannes
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