I did the test both ways again just to be sure I wasn't fooling myself, and -spinlock 10000 totally eliminates the performance issue in Test.
Just for the hell of it, I ran the 34-process spawner 4 more times in one test, checking performance each time, so eventually I had 170 processes running at once. It took a little longer for screens to come back (we were beating the 2 Test CPUs pretty hard) but the DB performance issue was still not seen.
Then the Unix guys came over and asked me what the hell I was doing...
Just for the hell of it, I ran the 34-process spawner 4 more times in one test, checking performance each time, so eventually I had 170 processes running at once. It took a little longer for screens to come back (we were beating the 2 Test CPUs pretty hard) but the DB performance issue was still not seen.
Then the Unix guys came over and asked me what the hell I was doing...