Just for something to do, I set off a bunch of kernel compiles last
night before I went home.  Each run was a pair of:

	make clean
	make -j <something>

where <something> == 1, 2, 3, 4, 5 and 10.

Here's the timing results:

	make -j 1:
		1228.890u 253.673s 27:57.53 88.3% 0+0k 21+9107io 3601pf+0w
		1226.280u 254.449s 27:43.82 88.9% 0+0k 9+9110io 3601pf+0w
	make -j 2:
		1253.525u 278.465s 26:24.93 96.6% 0+0k 21+9425io 3602pf+0w
		1255.721u 278.033s 26:23.47 96.8% 0+0k 21+9431io 3602pf+0w
	make -j 3:
		1267.517u 279.625s 26:20.60 97.8% 0+0k 20+9476io 3602pf+0w
		1260.947u 279.276s 26:13.59 97.8% 0+0k 21+9470io 3602pf+0w
	make -j 4:
		1274.441u 280.777s 26:26.37 98.0% 0+0k 9+9507io 3606pf+0w 
		1271.042u 282.688s 26:26.64 97.9% 0+0k 21+9493io 3602pf+0w
	make -j 5: 
		1275.491u 281.621s 26:31.06 97.8% 0+0k 21+9523io 3602pf+0w
		1280.704u 282.510s 26:42.65 97.5% 0+0k 21+9534io 3602pf+0w
	make -j 10:
		1288.901u 291.356s 26:49.02 98.2% 0+0k 9+9668io 3602pf+0w 
		1291.650u 289.760s 26:55.39 97.8% 0+0k 17+9686io 3602pf+0w


"make -j 3" is a winner, saving approx. a minute and a half over just
a normal "make" (or about 5%) based on the fastest timimgs.  It's sort
of interesting that there's a similar number of page faults for each -j
option (pretty much 3602 always), but the number of io's varies a bit
(between 9107 and 9686) as the number of concurrent jobs goes up.

This is on a 5000/260 running 1.3.1, with the source tree mounted of
another 5000/260 running Ultrix 4.5 with PrestoServe.


On an entirely different note, here's some timings for the "crafty" chess
program calculating it's own performance (over three runs):

	DECstation 5000/260 NetBSD 1.3.1 - NetBSD binary (gcc 2.7.2.2+myc1 -O2):
		generated 480769 moves per second
		generated 479616 moves per second
		generated 480769 moves per second

	DECstation 5000/260 NetBSD 1.3.1 - Ultrix binary (gcc 2.7.2.2 -O2):
		generated 614088 moves per second
		generated 614576 moves per second
		generated 615244 moves per second

	DECstation 5000/260 Ultrix 4.5 - Ultrix binary (gcc 2.7.2.2 -O2):
		generated 587867 moves per second
		generated 589220 moves per second
		generated 587868 moves per second

In all cases, these were totally unloaded machines.  I haven't even
thought about analysing these results...


Simon.