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 марта 2015 г., at 8:53, Peter Jeremy <peter@rulingia.com> wrote: > > On 2015-Mar-22 00:58:55 +0300, Dmitry Sivachenko <trtrmitya@gmail.com> wrote: >> I have a machine with the following processor: >> >> CPU: Intel(R) Xeon(R) CPU E5620 @ 2.40GHz (2400.14-MHz K8-class CPU) >> Origin="GenuineIntel" Id=0x206c2 Family=0x6 Model=0x2c Stepping=2 > ... >> 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 >> % > > What OIDs do you have? Does dev.cpu.0 exist? How about dev.cpu? dev.cpu.0 does exist. 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 ============================================================================== --- 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="isa" hint.attimer.0.port="0x40" hint.attimer.0.irq="0" hint.wbwd.0.at="isa" +hint.acpi_throttle.0.disabled="1" +hint.p4tcc.0.disabled="1" If I remove that hint.p4tcc.0.disabled="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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