Arrgh. There was a stupid mistake. I forgot to add -O2 to COPTS in
/etc/mk.conf. Sorry for the wrong results. 

I did the same tests again, this time with proper COPTS. To eliminate
cache effects, I rebooted the machines between the tests.

		Athlon XP 1700  Pentium 166  Pentium 166  Pentium 166 
		    w/256MB	   w/64MB       w/32MB	     w/16MB	
-O2 (default)	    6:15          1:12:18      1:13:13      6:34:40
-pipe -O2	    6:04          1:12:55      1:13:32     manually
							  aborted at
				 	                   10:58:44		
Improvement	     3%	            -1%          -0%       -100%???

Now, it is clear that -pipe doesn't boost up kernel compile on a
slow machine. You can benefit from it with a fast machine with enough
memory.

A better method to speed up build is to simply not use any optimization
options like -O2.

Jun-Young

-- 
Bang Jun-Young <junyoung@mogua.com>