Show dirty buffers and the percentage of time a disk was busy.

PR:		12858
Submitted by:	Arjan de Vet <Arjan.deVet@adv.iae.nl>

2 files changed, 37 insertions, 14 deletions

diff --git a/usr.bin/systat/systat.1 b/usr.bin/systat/systat.1
index cc1272a..9d870c4 100644
--- a/usr.bin/systat/systat.1
+++ b/usr.bin/systat/systat.1
@@ -30,7 +30,7 @@
 .\" SUCH DAMAGE.
 .\"
 .\"	@(#)systat.1	8.2 (Berkeley) 12/30/93
-.\"	$Id$
+.\"	$Id: systat.1,v 1.18 1999/07/12 20:24:00 nik Exp $
 .\"
 .Dd September 9, 1997
 .Dt SYSTAT 1
@@ -306,9 +306,9 @@ handled by the per process name translation cache.
 .Pp
 At the bottom left is the disk usage display.
 It reports the number of
-kilobytes per transaction, transactions per second and megabytes 
-per second averaged over the 
-refresh period of the display (by default, five seconds).
+kilobytes per transaction, transactions per second, megabytes 
+per second and the percentage of the time the disk was busy averaged
+over the refresh period of the display (by default, five seconds).
 The system keeps statistics on most every storage device.  In general, up
 to seven devices are displayed.  The devices displayed by default are the
 first devices in the kernel's device list.  See 
@@ -351,6 +351,7 @@ per second over the refresh interval.
 .Pp
 At the bottom of this column are lines showing the
 amount of memory, in kilobytes, used for the buffer cache (`buf'),
+the number of dirty buffers in the buffer cache (`dirtybuf'),
 desired maximum size of vnode cache (`desiredvnodes') (mostly unused,
 except to size the name cache),
 number of vnodes actually allocated (`numvnodes'),
diff --git a/usr.bin/systat/vmstat.c b/usr.bin/systat/vmstat.c
index 9deac76..d3b5a68 100644
--- a/usr.bin/systat/vmstat.c
+++ b/usr.bin/systat/vmstat.c
@@ -36,7 +36,7 @@
 static char sccsid[] = "@(#)vmstat.c	8.2 (Berkeley) 1/12/94";
 #endif
 static const char rcsid[] =
-	"$Id: vmstat.c,v 1.34 1999/02/08 02:39:45 dillon Exp $";
+	"$Id: vmstat.c,v 1.35 1999/03/22 03:44:01 bde Exp $";
 #endif /* not lint */
 
 /*
@@ -82,6 +82,7 @@ static struct Info {
 	int	desiredvnodes;
 	long	numvnodes;
 	long	freevnodes;
+	long	numdirtybuffers;
 } s, s1, s2, z;
 
 struct statinfo cur, last, run;
@@ -164,6 +165,8 @@ static struct nlist namelist[] = {
 	{ "_numvnodes" },
 #define	X_FREEVNODES	10
 	{ "_freevnodes" },
+#define X_NUMDIRTYBUFFERS 11
+	{ "_numdirtybuffers" },
 	{ "" },
 };
 
@@ -310,10 +313,11 @@ labelkre()
 	mvprintw(VMSTATROW + 11, VMSTATCOL + 10, "pdpgs");
 	mvprintw(VMSTATROW + 12, VMSTATCOL + 10, "intrn");
 	mvprintw(VMSTATROW + 13, VMSTATCOL + 10, "buf");
+	mvprintw(VMSTATROW + 14, VMSTATCOL + 10, "dirtybuf");
 
-	mvprintw(VMSTATROW + 14, VMSTATCOL + 10, "desiredvnodes");
-	mvprintw(VMSTATROW + 15, VMSTATCOL + 10, "numvnodes");
-	mvprintw(VMSTATROW + 16, VMSTATCOL + 10, "freevnodes");
+	mvprintw(VMSTATROW + 15, VMSTATCOL + 10, "desiredvnodes");
+	mvprintw(VMSTATROW + 16, VMSTATCOL + 10, "numvnodes");
+	mvprintw(VMSTATROW + 17, VMSTATCOL + 10, "freevnodes");
 
 	mvprintw(GENSTATROW, GENSTATCOL, "  Csw  Trp  Sys  Int  Sof  Flt");
 
@@ -330,6 +334,7 @@ labelkre()
 	mvprintw(DISKROW + 1, DISKCOL, "KB/t");
 	mvprintw(DISKROW + 2, DISKCOL, "tps");
 	mvprintw(DISKROW + 3, DISKCOL, "MB/s");
+	mvprintw(DISKROW + 4, DISKCOL, "%% busy");
 	/*
 	 * For now, we don't support a fourth disk statistic.  So there's
 	 * no point in providing a label for it.  If someone can think of a
@@ -504,9 +509,10 @@ showkre()
 	}
 
 	putint(s.bufspace/1024, VMSTATROW + 13, VMSTATCOL, 9);
-	putint(s.desiredvnodes, VMSTATROW + 14, VMSTATCOL, 9);
-	putint(s.numvnodes, VMSTATROW + 15, VMSTATCOL, 9);
-	putint(s.freevnodes, VMSTATROW + 16, VMSTATCOL, 9);
+	putint(s.numdirtybuffers, VMSTATROW + 14, VMSTATCOL, 9);
+	putint(s.desiredvnodes, VMSTATROW + 15, VMSTATCOL, 9);
+	putint(s.numvnodes, VMSTATROW + 16, VMSTATCOL, 9);
+	putint(s.freevnodes, VMSTATROW + 17, VMSTATCOL, 9);
 	PUTRATE(Cnt.v_vnodein, PAGEROW + 2, PAGECOL + 5, 5);
 	PUTRATE(Cnt.v_vnodeout, PAGEROW + 2, PAGECOL + 10, 5);
 	PUTRATE(Cnt.v_swapin, PAGEROW + 2, PAGECOL + 17, 5);
@@ -736,6 +742,7 @@ getinfo(s, st)
 	NREAD(X_FREEVNODES, &s->freevnodes, LONG);
 	NREAD(X_NCHSTATS, &s->nchstats, sizeof s->nchstats);
 	NREAD(X_INTRCNT, s->intrcnt, nintr * LONG);
+	NREAD(X_NUMDIRTYBUFFERS, &s->numdirtybuffers, sizeof(s->numdirtybuffers));
 	size = sizeof(s->Total);
 	mib[0] = CTL_VM;
 	mib[1] = VM_METER;
@@ -800,24 +807,39 @@ dinfo(dn, c, now, then)
 {
 	long double transfers_per_second;
 	long double kb_per_transfer, mb_per_second;
-	long double busy_seconds;
+	long double elapsed_time, device_busy;
 	int di;
 
 	di = dev_select[dn].position;
 
-	busy_seconds = compute_etime(now->busy_time, then ?
+	elapsed_time = compute_etime(now->busy_time, then ?
 				     then->busy_time :
 				     now->dinfo->devices[di].dev_creation_time);
 
+	device_busy =  compute_etime(now->dinfo->devices[di].busy_time, then ?
+				     then->dinfo->devices[di].busy_time :
+				     now->dinfo->devices[di].dev_creation_time);
+
 	if (compute_stats(&now->dinfo->devices[di], then ?
-			  &then->dinfo->devices[di] : NULL, busy_seconds,
+			  &then->dinfo->devices[di] : NULL, elapsed_time,
 			  NULL, NULL, NULL,
 			  &kb_per_transfer, &transfers_per_second,
 			  &mb_per_second, NULL, NULL) != 0)
 		errx(1, "%s", devstat_errbuf);
 
+	if ((device_busy == 0) && (transfers_per_second > 5))
+		/* the device has been 100% busy, fake it because
+		 * as long as the device is 100% busy the busy_time
+		 * field in the devstat struct is not updated */
+		device_busy = elapsed_time;
+	if (device_busy > elapsed_time)
+		/* this normally happens after one or more periods
+		 * where the device has been 100% busy, correct it */
+		device_busy = elapsed_time;
+
 	c = DISKCOL + c * 6;
 	putlongdouble(kb_per_transfer, DISKROW + 1, c, 5, 2, 0);
 	putlongdouble(transfers_per_second, DISKROW + 2, c, 5, 0, 0);
 	putlongdouble(mb_per_second, DISKROW + 3, c, 5, 2, 0);
+	putlongdouble(device_busy * 100 / elapsed_time, DISKROW + 4, c, 5, 0, 0);
 }