Irritating whine in new 9.0 install

[davidgurvich]

Every once in a while I test various operating systems on an older problem laptop that I have(thinkpad X30:1.2GHz P3,1GB ram, i830 graphics). So far FreeBSD has not worked well on it. Suspend/resume fails and other issues including slowness in switching between programs and a completely unworkable wireless. These are all issues that don't exist on PCLinuxOS or OpenBSD.

This past week I decided to see how ZFS and other things are working with FreeBSD-9.0. Almost immediately after installing I couldn't wait to get rid of it. There was an annoying high-pitched whine that I couldn't stand. I tried ataidle and a number of other settings but nothing worked. I thought it might have something to do with the fact that I haven't disabled WITNESS or debugging in the kernel.

Turns out that the kern.hz setting was 1000. Setting

kern.hz=100

got rid of the irritating whine.

As a side note the problems that plagued wireless and networking in general and caused me to stop using FreeBSD seem to be better.

 

[shepper]

I had this same issue in an old laptop based on an Via C3 800mHz cpu.

My searches in this forum and Google indicated this is a common solution and that performance does not usually suffer. My question is what am I actually setting? It does not seem like my single core CPU is running at 100Hz which would be the cpu clock speed. Does it have to do with the memory? I think the laptop has PC133 memory.

2nd Edit: I found this link. It is an interrupt and appears to have a significant affect on power consumption.