svn commit: r193839 - stable/6/sys/kern

[Attilio Rao]

Author: attilio
Date: Tue Jun  9 15:50:33 2009
New Revision: 193839
URL: http://svn.freebsd.org/changeset/base/193839

Log:
  MFC r156484:
  Add slop to "backwards" cpu accounting messages, 3 usec or 1% whichever
  triggers.  That will improve the diagnostic with 'time went backwards'
  messages.
  
  Sponsored by:	Sandvine Incorporated

Modified:
  stable/6/sys/kern/kern_resource.c

Modified: stable/6/sys/kern/kern_resource.c
==============================================================================
--- stable/6/sys/kern/kern_resource.c	Tue Jun  9 15:20:36 2009	(r193838)
+++ stable/6/sys/kern/kern_resource.c	Tue Jun  9 15:50:33 2009	(r193839)
@@ -773,7 +773,11 @@ calcru1(p, ruxp, up, sp)
 	bintime2timeval(&ruxp->rux_runtime, &tv);
 	tu = (u_int64_t)tv.tv_sec * 1000000 + tv.tv_usec;
 	ptu = ruxp->rux_uu + ruxp->rux_su + ruxp->rux_iu;
-	if (tu < ptu) {
+	if (tu + 3 > ptu) {
+		/* Numeric slop for low counts */
+	} else if (101 * tu > 100 * ptu) {
+		/* 1% slop for large counts */
+	} else {
 		printf(
 "calcru: runtime went backwards from %ju usec to %ju usec for pid %d (%s)\n",
 		    (uintmax_t)ptu, (uintmax_t)tu, p->p_pid, p->p_comm);