[src/trunk]: src/sys/kern cpu times were miscalculated because 'usecs' could ...

[dsl <dsl%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/74a5c602df53
branches:  trunk
changeset: 544214:74a5c602df53
user:      dsl <dsl%NetBSD.org@localhost>
date:      Fri Mar 14 21:38:26 2003 +0000

description:
cpu times were miscalculated because 'usecs' could go -ve...
There is still a problem that 'st = (u * st) / tot;' can overflow,
but that is harder to fix, and requires cpu times of ~5days.
(approved by christos)

diffstat:

 sys/kern/kern_resource.c |  37 +++++++++++++------------------------
 1 files changed, 13 insertions(+), 24 deletions(-)

diffs (80 lines):

diff -r 499a876bf187 -r 74a5c602df53 sys/kern/kern_resource.c
--- a/sys/kern/kern_resource.c  Fri Mar 14 21:24:44 2003 +0000
+++ b/sys/kern/kern_resource.c  Fri Mar 14 21:38:26 2003 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: kern_resource.c,v 1.69 2003/03/05 11:44:01 dsl Exp $   */
+/*     $NetBSD: kern_resource.c,v 1.70 2003/03/14 21:38:26 dsl Exp $   */
 
 /*-
  * Copyright (c) 1982, 1986, 1991, 1993
@@ -41,7 +41,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: kern_resource.c,v 1.69 2003/03/05 11:44:01 dsl Exp $");
+__KERNEL_RCSID(0, "$NetBSD: kern_resource.c,v 1.70 2003/03/14 21:38:26 dsl Exp $");
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -390,7 +390,8 @@
        struct timeval *ip;
 {
        u_quad_t u, st, ut, it, tot;
-       unsigned long sec, usec;
+       unsigned long sec;
+       long usec;
        int s;
        struct timeval tv;
        struct lwp *l;
@@ -403,8 +404,7 @@
 
        sec = p->p_rtime.tv_sec;
        usec = p->p_rtime.tv_usec;
-       for (l = LIST_FIRST(&p->p_lwps); l != NULL; 
-            l = LIST_NEXT(l, l_sibling)) {
+       LIST_FOREACH(l, &p->p_lwps, l_sibling) {
                if (l->l_stat == LSONPROC) {
                        struct schedstate_percpu *spc;
                        
@@ -425,33 +425,22 @@
        }
 
        tot = st + ut + it;
+       u = sec * 1000000ull + usec;
+
        if (tot == 0) {
                /* No ticks, so can't use to share time out, split 50-50 */
-               if (usec > 1000000 && (sec & 1)) {
-                       usec -= 1000000;
-                       sec++;
-               } else {
-                       if (sec & 1) {
-                               usec += 1000000;
-                               sec--;
-                       }
-               }
-               up->tv_sec = sp->tv_sec = sec / 2;
-               up->tv_usec = sp->tv_usec = usec / 2;
-               if (ip != NULL)
-                       ip->tv_sec = ip->tv_usec = 0;
-               return;
+               st = ut = u / 2;
+       } else {
+               st = (u * st) / tot;
+               ut = (u * ut) / tot;
        }
-
-       u = (u_quad_t) sec * 1000000 + usec;
-       st = (u * st) / tot;
        sp->tv_sec = st / 1000000;
        sp->tv_usec = st % 1000000;
-       ut = (u * ut) / tot;
        up->tv_sec = ut / 1000000;
        up->tv_usec = ut % 1000000;
        if (ip != NULL) {
-               it = (u * it) / tot;
+               if (it != 0)
+                       it = (u * it) / tot;
                ip->tv_sec = it / 1000000;
                ip->tv_usec = it % 1000000;
        }