interactive performance patch from NetBSD

[Matthieu Herrb <matthieu@laas.fr>]

Hi,

I found that the following patch (From NetBSD by Ross Harvey and Bill
Sommerfeld) greatly improve interactive performance (while compiling
the whole system under X11 for instance) on OpenBSD too. 

I think this solves all the 'sluggish mouse' problems that were
reported. 

This was discussed on NetBSD's tech-kern mailing list last january
in the 'sucky performance' thread
(archived at <http://mail-index.netbsd.org/tech-kern/1999/01/>). Since 
it was a significant update on my NetBSD machine, I wanted to try it
on OpenBSD for a long time. Ross has recently made it easier by
sending a patch against NetBSD 1.3 source. I merged it into
OpenBSD-current, and it works for me. 

Index: kern_exit.c
===================================================================
RCS file: /cvs/src/sys/kern/kern_exit.c,v
retrieving revision 1.16
diff -u -u -r1.16 kern_exit.c
--- kern_exit.c	1999/03/02 22:19:09	1.16
+++ kern_exit.c	1999/03/12 07:52:32
@@ -368,6 +368,11 @@
 				wakeup((caddr_t)t);
 				return (0);
 			}
+
+			/* Charge us for our child's sins */
+			curproc->p_estcpu = min(curproc->p_estcpu +
+						p->p_estcpu, UCHAR_MAX);
+
 			p->p_xstat = 0;
 			ruadd(&q->p_stats->p_cru, p->p_ru);
 			FREE(p->p_ru, M_ZOMBIE);
Index: kern_fork.c
===================================================================
RCS file: /cvs/src/sys/kern/kern_fork.c,v
retrieving revision 1.19
diff -u -u -r1.19 kern_fork.c
--- kern_fork.c	1999/03/02 22:19:08	1.19
+++ kern_fork.c	1999/03/12 07:52:32
@@ -297,6 +297,13 @@
 	}
 #endif
 
+        /*
+         * set priority of child to be that of parent
+	 * XXX should move p_estcpu into the region of struct proc which gets
+	 * copied.
+         */
+        p2->p_estcpu = p1->p_estcpu;
+
 	/*
 	 * This begins the section where we must prevent the parent
 	 * from being swapped.


					Matthieu