idle process keeping cpu 150% busy in freebsd 9.1-amd64

[Kostas Oikonomou]

Thanks very much for the reply.

Being new to FreeBSD, this still seems weird to me.  (My 
background is Solaris.)

On both machines, the core that's running at 150% in the 
case of the HP machine, and at 400% in the case
of the Dell laptop, is causing the fans to come on.  Would 
you call that "idle"?  I'm worried that the cores will
eventually be damaged.

                             Kostas

On 05/31/13 08:36 AM, John Baldwin wrote:
> On Thursday, May 30, 2013 4:29:07 pm Kostas Oikonomou wrote:
>>     Hello,
>>     I am new to FreeBSD. I just installed 9.1-RELEASE-p3 (comes with PC-BSD
>>     9.1) on an HP Pavilion s5100z.  The machine has a dual-core AMD Athlon
>>     7750 processor.
>>     What happens is that when I am doing nothing on the machine, one core
>>     is about 150%
>>     busy running the idle process:
>>     USER        PID  %CPU %MEM    VSZ   RSS TT  STAT STARTED    TIME
>>     COMMAND
>>     root         11 152.9  0.0      0    32 ??  RL    8:19AM 2:14.50 [idle]
>>     root          0   0.0  0.1      0  2672 ??  DLs   8:19AM 0:00.36
>>     [kernel]
>>     root          1   0.0  0.0   6276   416 ??  SLs   8:19AM 0:00.05
>>     /sbin/init --
>>     I have read [1]http://forums.freebsd.org/showthread.php?t=38757, which
>>     seems to be relevant, and I tried
>>     sysctl -w kern.eventtimer.timer=<various choices>
>>     as they suggest, but to no avail.
>>     The same problem also on my Dell E6510 laptop, which has an Intel Core
>>     i7:  the idle process is making one core run at about 400%.
>>     Any help would be greatly appreciated.
>>                                 Kostas
> This is normal.  The idle process has a thread per-CPU that the scheduler runs
> when the CPU is idle.  Even if the CPU is actually asleep in a Cx state, the
> time it is asleep is accounted to the idle thread.
>
> I added a 'Z' flag to hide the idle threads in top (they are especially
> noisy on an idle machine with a lot of CPUs if you use top -SH).
>