Date: Sun, 22 Mar 2015 12:05:49 +0300 From: Dmitry Sivachenko <trtrmitya@gmail.com> To: Peter Jeremy <peter@rulingia.com> Cc: FreeBSD Stable ML <stable@freebsd.org>, nwhitehorn@freebsd.org Subject: Re: dev.cpu.0.freq disapeared Message-ID: <77C8F6F7-2C25-4BC5-B373-11441AB58FAD@gmail.com> In-Reply-To: <20150322055323.GA48710@server.rulingia.com> References: <EE8D6553-4319-4CE1-8F73-3244C49F454C@gmail.com> <20150322055323.GA48710@server.rulingia.com>
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> On 22 =D0=BC=D0=B0=D1=80=D1=82=D0=B0 2015 =D0=B3., at 8:53, Peter = Jeremy <peter@rulingia.com> wrote: >=20 > On 2015-Mar-22 00:58:55 +0300, Dmitry Sivachenko <trtrmitya@gmail.com> = wrote: >> I have a machine with the following processor: >>=20 >> CPU: Intel(R) Xeon(R) CPU E5620 @ 2.40GHz (2400.14-MHz = K8-class CPU) >> Origin=3D"GenuineIntel" Id=3D0x206c2 Family=3D0x6 Model=3D0x2c = Stepping=3D2 > ... >> After I upgraded to 10.1-STABLE #0 r279956, this sysctl disapeared. >> % sysctl dev.cpu.0.freq >> sysctl: unknown oid 'dev.cpu.0.freq': No such file or directory >> % >=20 > What OIDs do you have? Does dev.cpu.0 exist? How about dev.cpu? dev.cpu.0 does exist. =20 I found the problematic change: Author: nwhitehorn Date: Sun Jan 11 17:10:07 2015 New Revision: 276986 URL: https://svnweb.freebsd.org/changeset/base/276986 Log: MFC r265329: Disable ACPI and P4TCC throttling by default, following discussion on freebsd-current. These CPU speed control techniques are usually = unhelpful at best. For now, continue building the relevant code into GENERIC so = that it can trivially be re-enabled at runtime if anyone wants it. Modified: stable/10/sys/amd64/conf/GENERIC.hints = =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D --- stable/10/sys/amd64/conf/GENERIC.hints Sun Jan 11 17:00:24 2015 = (r276985) +++ stable/10/sys/amd64/conf/GENERIC.hints Sun Jan 11 17:10:07 2015 = (r276986) @@ -31,3 +31,5 @@ hint.attimer.0.at=3D"isa" hint.attimer.0.port=3D"0x40" hint.attimer.0.irq=3D"0" hint.wbwd.0.at=3D"isa" +hint.acpi_throttle.0.disabled=3D"1" +hint.p4tcc.0.disabled=3D"1" If I remove that hint.p4tcc.0.disabled=3D"1" from device.hints, = dev.cpu.0.freq appears back again. I am using dev.cpu.0.freq to ensure that processor is running at = expected frequency (with some buggy BIOSes or buggy BIOS options = combinations it is possible to end up with machine running at half = frequency). Does it really hurt to have this sysctl available? Why it was disabled = by default? (I am not discussing hint.acpi_throttle.0.disabled here, just = hint.p4tcc.0.disabled). Thanks.
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