Linda Messerschmidt wrote:
Well, this is interesting. I got really frustrated with the other
approach, so I thought I'd thin a machine down absolutely as far as I
could, eliminate every possible source of delay, and see what happens.
I killed everything... cron, RPC, NFS, devd, gmon, nrpe, everything.
The Apache and its exerciser are now the only things running on the
machine, and the Apache is only touching an md0 swap device mounted on
/mnt. I *still* get the hangs.
It hangs for all sorts of different periods, but the duration of the
stall is approximately inversely proportional to the chance of seeing
it. To get a short delay, you need wait only a little bit. If you
want a 2-3 second delay, you may have to wait 15-20 minutes.
On what sort of hardware is this hang occurring? Several months ago I
was trying to resolve an intermittent hang under FreeBSD 7. I collected
a large number of crashdumps I created using the kernel debugger when I
caught the machine hanging, but the backtraces were very inconsistent,
and the hang was only occurring on Xeons with multithreading (older
2.8GHz and 3.6GHz Xeons). I was able to prevent the hang by setting
"mach.hyperthreading_enabled=0" in /boot/loader.conf, but I am still not
sure why it worked.
Guy
_______________________________________________
freebsd-hackers@freebsd.org mailing list
http://lists.freebsd.org/mailman/listinfo/freebsd-hackers
To unsubscribe, send any mail to "freebsd-hackers-unsubscr...@freebsd.org"
