2 x quad-core system is slower that 2 x dual core on FreeBSD

Kris Kennaway kris at FreeBSD.org
Mon Nov 19 10:46:41 PST 2007

Alexey Popov wrote:
> Hi.
> Ivan Voras wrote:
>>> CPU states:  9.5% user,  0.0% nice, 82.0% system,  0.5% interrupt,  8.0%
>>> idle
>> A wild idea that might not help: try reducing kern.hz in loader.conf to
>> something like 100 and see if something significant changes.
> Now it runs with hz=100, number of context switches became ~ 2 times
> less, but still there's 90% system CPU load (see attach).

System CPU usage doesn't tell you anything by itself, you need to look 
at how much work the system is actually doing (pages served/second, or 
whatever).  For example, when your kernel is getting more work done, 
system CPU usage will also be higher.


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