amd64/127451: top(1): incorrect load shown on quad core

[Kris Kennaway]

Tomas Randa wrote:
> I have similar problem on my Xeon5000 quad core system with 7.1 
> PRERELEASE / AMD64. Tried anybody to change scheduler from ULE to 4BSD?
> I tried to change some sysctl variables, but no success.
> 
> Thanks for help.
> 
> Tomas Randa
> 
> 
> ===============================
> 
> From: miks at skynet.lv
> To: bug-followup at FreeBSD.org, miks at skynet.lv
> Cc:  Subject: Re: amd64/127451: top(1): incorrect load shown on quad core
> Date: Thu, 18 Sep 2008 21:50:06 +0300
> 
> 
> 
> I got load average around 0.5, and top show something like this
> "1021 processes: 1 running, 1020 sleeping
> CPU states:  4.9% user,  0.0% nice,  3.6% system,  0.9% interrupt,
> 90.6% idle" - this all is ok.
> 
> then once in 2-5 minutes, there for 2-3 seconds are:
> "1020 processes:67 running, 912 sleeping, 1 zombie, 40 lock
> CPU states:  3.0% user,  0.0% nice, 96.7% system,  0.3% interrupt,
> 0.0% idle" - this is the problem.
> 
> after this load average is 20-30 and dropping in 2-3min to 0.5. during
> this time system is very slow. even ssh session is freezing.
> most of processes are fastcgi/php, so there is not one big resource
> hungry process.
> 
> found similar problem here: 
> http://unix.derkeiler.com/Mailing-Lists/FreeBSD/stable/2007-11/msg00551.html 

I sam not sure what you are claiming the problem is.  Your system is 
being transiently overloaded by processes that eat all CPU, and that is 
what top shows you.

Kris