aki's suggested fix to profile to make it work in default mode.
it worked for me

Reference: /n/sources/patch/applied/profile-fix
Date: Sat Feb  7 16:33:25 CET 2009
Signed-off-by: forsyth@terzarima.net

--- /sys/src/libc/port/profile.c	Sat Feb  7 16:32:32 2009
+++ /sys/src/libc/port/profile.c	Sat Feb  7 16:32:30 2009
@@ -142,7 +142,7 @@
 		break;
 	case Profuser:
 		cycles((uvlong*)&_tos->prof.first->time);
-		_tos->prof.first->time = _tos->prof.first->time + _tos->kcycles;
+		_tos->prof.first->time = _tos->prof.first->time - _tos->kcycles;
 		break;
 	case Proftime:
 		cycles((uvlong*)&_tos->prof.first->time);