> do you have numbers to back up this claim?
>
> you are claiming that the locked XCHGL
> in tas (pc/l.s) called from lock (port/taslock.c)
> called from incref (port/chan.c) is "much faster"
> than the locked INCL in _xinc (pc/l.s).
> it seems to me that a locked memory bus
> is a locked memory bus.

yes, i do.  xinc on most modern intel is a real
loss.  and a moderate loss on amd.  my atom 330
is an exception.

intel core i7 2.4ghz
loop	0 nsec/call
loopxinc	20 nsec/call
looplock	11 nsec/call

intel 5000 1.6ghz
loop	0 nsec/call
loopxinc	44 nsec/call
looplock	25 nsec/call

intel atom 330 1.6ghz (exception!)
loop	2 nsec/call
loopxinc	14 nsec/call
looplock	22 nsec/call

amd k10 2.0ghz
loop	2 nsec/call
loopxinc	30 nsec/call
looplock	20 nsec/call

intel p4 xeon 3.0ghz

loop	1 nsec/call
loopxinc	76 nsec/call
looplock	42 nsec/call

- erik