FreeBSD 5.2.1: Mutex/Spinlock starvation?

[Robert Watson]

On Mon, 7 Jun 2004, Ali Niknam wrote:

> > There isn't a timeout.  Rather, the lock spins so long as the current
> > owning thread is executing on another CPU.
> 
> Interesting. Is there a way to 'lock' CPU's so that they always run on
> 'another' CPU ?
> 
> Unfortunately as we speak the server is down again :( This all makes me
> wonder wether I should simply go back to 4.10.
> I decreased the maximum number of apache children to 1400 and the server
> seems to be barely holding on:
> last pid:  2483;  load averages: 75.77, 28.63, 11.40    up 0+00:04:32
> 19:35:07
> 1438 processes:2 running, 294 sleeping, 1142 lock
> CPU states:  6.2% user,  0.0% nice, 62.6% system,  7.5% interrupt, 23.8%
> idle
> Mem: 698M Active, 27M Inact, 209M Wired, 440K Cache, 96M Buf, 1068M Free
> Swap: 512M Total, 512M Free
> 
> Are there anymore quite stable things to do ? That is except for upping
> to current, which I frankly feel is too dangerous... 

Is there any way you can give us a "top -S" output snapshot of your full
set of processes, if necessary omitting sensitive process names, etc?

Also, can you give a snapshot of "vmstat -systat" once it's settled for a
few iterations?

Robert N M Watson             FreeBSD Core Team, TrustedBSD Projects
robert at fledge.watson.org      Senior Research Scientist, McAfee Research