Index: contrib/top/commands.c
===================================================================
--- contrib/top/commands.c	(revision 221924)
+++ contrib/top/commands.c	(working copy)
@@ -94,6 +94,7 @@
 a       - toggle the displaying of process titles\n\
 t       - toggle the display of this process\n\
 u       - display processes for only one user (+ selects all users)\n\
+z       - toggle the displaying of system idle process\n\
 \n\
 \n", stdout);
     }
Index: contrib/top/top.c
===================================================================
--- contrib/top/top.c	(revision 221924)
+++ contrib/top/top.c	(working copy)
@@ -196,9 +196,9 @@
     fd_set readfds;
 
 #ifdef ORDER
-    static char command_chars[] = "\f qh?en#sdkriIutHmSCajo";
+    static char command_chars[] = "\f qh?en#sdkriIutHmSCajzo";
 #else
-    static char command_chars[] = "\f qh?en#sdkriIutHmSCaj";
+    static char command_chars[] = "\f qh?en#sdkriIutHmSCajz";
 #endif
 /* these defines enumerate the "strchr"s of the commands in command_chars */
 #define CMD_redraw	0
@@ -224,8 +224,9 @@
 #define	CMD_wcputog	19
 #define	CMD_showargs	20
 #define	CMD_jidtog	21
+#define CMD_kidletog	22
 #ifdef ORDER
-#define CMD_order       22
+#define CMD_order       23
 #endif
 
     /* set the buffer for stdout */
@@ -258,6 +259,7 @@
     ps.thread  = No;
     ps.wcpu    = 1;
     ps.jail    = No;
+    ps.kidle   = Yes;
     ps.command = NULL;
 
     /* get preset options from the environment */
@@ -283,7 +285,7 @@
 	    optind = 1;
 	}
 
-	while ((i = getopt(ac, av, "CSIHPabijnquvs:d:U:m:o:t")) != EOF)
+	while ((i = getopt(ac, av, "CSIHPabijnquvzs:d:U:m:o:t")) != EOF)
 	{
 	    switch(i)
 	    {
@@ -412,10 +414,14 @@
 		pcpu_stats = Yes;
 		break;
 
+	      case 'z':
+		ps.kidle = !ps.kidle;
+		break;
+
 	      default:
 		fprintf(stderr,
 "Top version %s\n"
-"Usage: %s [-abCHIijnPqStuv] [-d count] [-m io | cpu] [-o field] [-s time]\n"
+"Usage: %s [-abCHIijnPqStuvz] [-d count] [-m io | cpu] [-o field] [-s time]\n"
 "       [-U username] [number]\n",
 			version_string(), myname);
 		exit(1);
@@ -1075,7 +1081,13 @@
 				reset_display();
 				putchar('\r');
 				break;
-	    
+			    case CMD_kidletog:
+				ps.kidle = !ps.kidle;
+				new_message(MT_standout | MT_delayed,
+				    " %sisplaying kernel idle process.",
+				    ps.idle ? "D" : "Not d");
+				putchar('\r');
+				break;
 			    default:
 				new_message(MT_standout, " BAD CASE IN SWITCH!");
 				putchar('\r');
Index: contrib/top/machine.h
===================================================================
--- contrib/top/machine.h	(revision 221924)
+++ contrib/top/machine.h	(working copy)
@@ -65,6 +65,7 @@
     int uid;		/* only this uid (unless uid == -1) */
     int wcpu;		/* show weighted cpu */
     int jail;		/* show jail ID */
+    int kidle;		/* show per-CPU idle threads */
     char *command;	/* only this command (unless == NULL) */
 };
 
Index: contrib/top/top.X
===================================================================
--- contrib/top/top.X	(revision 221924)
+++ contrib/top/top.X	(working copy)
@@ -10,7 +10,7 @@
 .SH SYNOPSIS
 .B top
 [
-.B \-abCHIijnPqStuv
+.B \-abCHIijnPqStuvz
 ] [
 .BI \-d count
 ] [
@@ -142,6 +142,9 @@
 No other processing takes place when this option is used.  To see current
 revision information while top is running, use the help command \*(lq?\*(rq.
 .TP
+.B \-z
+Do not display the system idle process.
+.TP
 .BI \-d count
 Show only
 .I count
@@ -303,6 +306,9 @@
 Toggle the display of the
 .I top
 process.
+.TP
+.B z
+Toggle the display of the system idle process.
 .SH "THE DISPLAY"
 The actual display varies depending on the specific variant of Unix
 that the machine is running.  This description may not exactly match
Index: usr.bin/top/machine.c
===================================================================
--- usr.bin/top/machine.c	(revision 221924)
+++ usr.bin/top/machine.c	(working copy)
@@ -623,6 +623,7 @@
 	int show_system;
 	int show_uid;
 	int show_command;
+	int show_kidle;
 
 	/*
 	 * Save the previous process info.
@@ -663,6 +664,7 @@
 	show_system = sel->system;
 	show_uid = sel->uid != -1;
 	show_command = sel->command != NULL;
+	show_kidle = sel->kidle;
 
 	/* count up process states and get pointers to interesting procs */
 	total_procs = 0;
@@ -704,6 +706,11 @@
 			/* skip idle or non-running processes */
 			continue;
 
+		if (displaymode == DISP_CPU && !show_kidle &&
+		    pp->ki_tdflags & TDF_IDLETD)
+			/* skip kernel idle process */
+			continue;
+		    
 		if (displaymode == DISP_IO && !show_idle && p_io == 0)
 			/* skip processes that aren't doing I/O */
 			continue;