> >Whereas, the typical result for the new rig looked more like
> > 105.36 real 71.10 user 33.41 sys
> > ...
> > 10548 involuntary context switches
> First of all, make sure that you have WITNESS and INVARIANTS off in your
> kernel. You might also want to recompile your kernel with the SMP
> option turned off.
First of all, thanks to Mike Tancsa for suggesting 5.4 RC4 and to Pete
French for running the test independently on the higher spec machines
with 5.4 RC4 on them, confirming the system time thing, ruling out an
AMD problem, dissociating the system time result from the context
switching, and saving me the trouble of rediscovering the same problem
on 5.4 RC4.
This is my first foray into the public world of FreeBSD discussion
lists, and I am encouraged by the helpfulness of the response.
Scott, the 5.3 kernel I had was a essentially a GENERIC release
kernel, with about 100 options commented out. WITNESS and INVARIANTS
are off by default, which I confirmed by looking through `sysctl -a`.
However, I was curious to see what I would get if I switched them on,
so I added these options and recompiled the kernel:
The result, below, has essentially the same user time (or just less,
if that makes any sense), but tripled system time. The context
switches are consistent with the one-per-10msec I saw before. Is
there anything useful I can do while I still have the kernel debug
172.29 real 67.53 user 103.07 sys
23376 maximum resident set size
659 average shared memory size
20805 average unshared data size
127 average unshared stack size
5402 page reclaims
0 page faults
0 block input operations
0 block output operations
0 messages sent
0 messages received
0 signals received
0 voluntary context switches
17234 involuntary context switches