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Date:      Thu, 14 May 2015 10:59:02 -0400
From:      mfv <mfv@bway.net>
To:        "William A. Mahaffey III" <wam@hiwaay.net>
Cc:        "FreeBSD Questions !!!!" <freebsd-questions@freebsd.org>
Subject:   Re: sysctl question
Message-ID:  <20150514105902.319e5f3f@gecko4>
In-Reply-To: <5554AD9D.9060201@hiwaay.net>
References:  <55541052.6020802@hiwaay.net> <20150514055826.01e841ae@gecko4> <5554ABEF.4070300@hiwaay.net> <5554AD9D.9060201@hiwaay.net>

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On Thu, 14 May 2015 09:20:04 -0453
"William A. Mahaffey III" <wam@hiwaay.net> wrote:

> On 05/14/15 09:12, William A. Mahaffey III wrote:
> > On 05/14/15 05:04, mfv wrote:
> >> Hello William,
> >>
> >> I had the same problem using amdtemp but used the sysctl setting
> >> "dev.amdtemp.%d.sensor_offset" to make it more accurate. The value
> >> was determined by comparing the unadjusted value of admtemp with
> >> the value shown in the BIOS.  In my case the setting
> >> in /etc/sysctl.conf is:
> >>
> >>   dev.amdtemp.0.sensor_offset=24
> >>
> >> A room thermometer was also helpful to measure the difference by
> >> comparing the difference between the room temperature and the BIOS
> >> after the CPU was placed under load.
> >>
> >> To read the value I then bound the F2-key in csh.cshrc file as
> >> follows:
> >>
> >>    bindkey -c "^[OQ" 'sysctl -e dev.amdtemp.0.core0'
> >>
> >> The results of the reading are not as accurate as I would like but
> >> are an improvement.
> >>
> >>      Cheers ...                                 __o
> >>                                               _ \<,_
> >>      Marek                                   (+)/ (+)
> >> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> >
> > P.S. Is there a way to set this on the fly, w/o a reboot ?
> > TIA :-) ....
> >
> 
> 
> [root@kabini1, /etc, 9:18:34am] 369 % sysctl
> dev.amdtemp.0.sensor_offset=24 sysctl: unknown oid
> 'dev.amdtemp.0.sensor_offset' [root@kabini1, /etc, 9:18:36am] 370 %
> sysctl amdtemp.0.sensor_offset=24 sysctl: unknown oid
> 'amdtemp.0.sensor_offset' [root@kabini1, /etc, 9:18:37am] 371 %
> sysctl -A | grep -i amdtemp dev.amdtemp.0.%desc: AMD CPU On-Die
> Thermal Sensors dev.amdtemp.0.%driver: amdtemp
> dev.amdtemp.0.%parent: hostb5
> dev.amdtemp.0.sensor0.core0: 10.0C
> [root@kabini1, /etc, 9:18:41am] 372 % uname -a
> FreeBSD kabini1.local 9.3-RELEASE-p13 FreeBSD 9.3-RELEASE-p13 #0: Tue 
> Apr  7 03:01:12 UTC 2015 
> root@amd64-builder.daemonology.net:/usr/obj/usr/src/sys/GENERIC amd64
> [wam@kabini1, ~, 9:19:39am] 399 %
> 
> 

Yes, it is possible to do it on the fly:

[10:55] ~ > 
dev.amdtemp.0.core0.sensor0=39.7C

[10:55] ~ > sudo sysctl dev.amdtemp.0.sensor_offset=0
dev.amdtemp.0.sensor_offset: 24 -> 0

[10:55] ~ > 
dev.amdtemp.0.core0.sensor0=15.7C

[10:55] ~ > sudo sysctl dev.amdtemp.0.sensor_offset=24
dev.amdtemp.0.sensor_offset: 0 -> 24

[10:55] ~ > 
dev.amdtemp.0.core0.sensor0=39.8C

The 1st, 3rd and 5th command line are the results of the binding of the
F2-key to the sysctl output.

The 2nd command line sets the offset to the default of 0 while the
4th command line sets it back to 24 which is normally set in
/etc/sysctl.conf.

Your value will probably be different.

Cheers ...

Marek



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