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.
Scott
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:
options KDB options DDB options INVARIANTS options INVARIANT_SUPPORT options WITNESS options WITNESS_SKIPSPIN
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 options on?
-e
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 swaps 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
5.3 ships with SMP turned on, which makes lock operations rather expensive on single-processor machines. 4.x does not have SMP
turned on by default. Would you be able to re-run your test with
SMP turned off?
Scott _______________________________________________ freebsd-stable@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-stable To unsubscribe, send any mail to "[EMAIL PROTECTED]"
