CPU temp's on core 2 duo, should they be significantly different?

[Frank Shute]

On Mon, Jun 23, 2008 at 09:49:16PM -0700, George Hartzell wrote:
>
> Frank Shute writes:
>  > [...]
>  > My top on 7.0 says "CPU states:" not "CPU:"
>  > 
>  > Are you sure you're running on 2 cores?
>  > 
>  > dmesg will tell you and top will have a "C" column with 0 or 1 in it.
>  > 
>  > If you're running on one core, it will explain the temperature
>  > discrepancy.
> 
> I'm almost certain that I'm running on 2 cores.
> 
> My /usr/bin/top says that it's version: 
> 
>    top: version 3.5beta12

Same as mine!?! I'm running:

$ uname -rms

FreeBSD 7.0-RELEASE amd64

> 
> It does the a C column with 0 and 1.
> 
> I created a big file full of random data and bzip'd it.
> 
> One copy of the file took 20 seconds.  Two copies, two processes ran
> in 20 seconds each.  Three copies, three processes too 32 seconds.
> 
> Tops tells me that some things are running on CPU0 and others are on
> CPU1.
> 
> My config file is a copy of GENERIC and includes 'options SMP'.  As
> the machine boots it talks about finding both CPUS.
> 
> Here's the config file:
> 
>   http://shrimp.alerce.com/bluetoo-info/BLUETOO.txt
> 
> Here's the verbose dmesg:
> 
>  http://shrimp.alerce.com/bluetoo-info/dmesg.verbose.txt
> 
> and my rc.conf:
> 
>  http://shrimp.alerce.com/bluetoo-info/rc.conf.txt
> 
> and here's top:
> 
>   last pid:  1650;  load averages:  0.00,  0.04,  0.11            up 0+02:43:22  21:47:06
>   51 processes:  1 running, 50 sleeping
>   CPU:  0.0% user,  0.0% nice,  0.0% system,  0.0% interrupt,  100% idle
>   Mem: 22M Active, 518M Inact, 200M Wired, 214M Buf, 3189M Free
>   Swap: 4063M Total, 4063M Free
>   
>     PID USERNAME    THR PRI NICE   SIZE    RES STATE  C   TIME   WCPU COMMAND
>     861 root          1  44    0  5688K  1148K select 1   0:01  0.00% powerd
>    1336 hartzell      1  44    0 33756K  4608K select 0   0:00  0.00% sshd
>     980 root          1  44    0 73860K  7192K select 1   0:00  0.00% httpd
>     854 root          1  44    0  9432K  2284K select 1   0:00  0.00% ntpd
>    1338 hartzell      1  20    0 10100K  3060K pause  1   0:00  0.00% tcsh
>     921 root          1   8    0  4600K   972K nanslp 1   0:00  0.00% svscan
>    1019 root          1  44    0 10696K  3868K select 1   0:00  0.00% sendmail
>     900 root          1  44    0 13416K  2772K select 1   0:00  0.00% nmbd
>    1104 hartzell      1   5    0 10100K  2752K ttyin  0   0:00  0.00% tcsh
>     943 dnscache      1  44    0  5624K  2368K select 1   0:00  0.00% dnscache
>    1333 root          1   4    0 33756K  4544K sbwait 1   0:00  0.00% sshd
>     733 root          1  44    0  5688K  1368K select 1   0:00  0.00% syslogd
>     942 root          1  44    0  6624K  1560K select 1   0:00  0.00% atalkd
>     971 avahi         1  44    0 15652K  2580K select 1   0:00  0.00% avahi-daemon
>     804 root          1  96    0  4604K  1424K select 0   0:00  0.00% nfsd
>    1092 root          1   8    0 20440K  1896K wait   1   0:00  0.00% login
>   
> g.

Well, it certainly seems that you're running on 2 cores so that blows
that theory out of the water :)

My next theory is that cpu0 is reporting too high a figure because
it's got a busted or miscalibrated thermistor (or whatever they use).

My machine reports cpu core temps of 22 & 24 respectively. That's
hovering about room temperature with powerd enabled and a virtually
idle machine.

For the record, I've got a Core 2 Duo E6550 2.33GHZ.

Another possibility, is that coretemp has a bug in it triggered by
your particular CPU. I think the broken temp sensor is more likely
though.

I don't know if your BIOS records the core temps. If not, it will
probably record the CPU temp in which case compare with your coretemp
temperatures. That may or may not cast some light on things and
whether you have to worry about the machine shutting down due to too
high a CPU temperature being erroneously recorded.

Regards,

-- 

 Frank 


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