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diff --git a/Disk/seeksize.d b/Disk/seeksize.d
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+++ b/Disk/seeksize.d
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+#!/usr/sbin/dtrace -s
+/*
+ * seeksize.d - analyse disk head seek distance by process.
+ *              Written using DTrace (Solaris 10 3/05).
+ *
+ * Disk I/O events caused by processes will in turn cause the disk heads
+ * to seek. This program analyses those seeks, so that we can determine
+ * if processes are causing the disks to seek in a "random" or "sequential"
+ * manner.
+ *
+ * $Id: seeksize.d 3 2007-08-01 10:50:08Z brendan $
+ *
+ * USAGE:	seeksize.d		# wait several seconds, then hit Ctrl-C
+ *
+ * FIELDS:
+ *		PID	process ID
+ *		CMD	command and argument list
+ *		value	distance in disk blocks (sectors)
+ *		count	number of I/O operations
+ *
+ * SEE ALSO: bitesize.d, iosnoop
+ *
+ * COPYRIGHT: Copyright (c) 2006 Brendan Gregg.
+ *
+ * CDDL HEADER START
+ *
+ *  The contents of this file are subject to the terms of the
+ *  Common Development and Distribution License, Version 1.0 only
+ *  (the "License").  You may not use this file except in compliance
+ *  with the License.
+ *
+ *  You can obtain a copy of the license at Docs/cddl1.txt
+ *  or http://www.opensolaris.org/os/licensing.
+ *  See the License for the specific language governing permissions
+ *  and limitations under the License.
+ *
+ * CDDL HEADER END
+ *
+ * 11-Sep-2004	Brendan Gregg	Created this.
+ * 10-Oct-2004	   "      "	Rewrote to use the io provider.
+ * 20-Apr-2006	   "      "	Last update.
+ */
+
+#pragma D option quiet
+
+/*
+ * Print header
+ */
+dtrace:::BEGIN
+{
+	printf("Tracing... Hit Ctrl-C to end.\n");
+}
+
+self int last[dev_t];
+
+/*
+ * Process io start
+ */
+io:genunix::start
+/self->last[args[0]->b_edev] != 0/
+{
+	/* calculate seek distance */
+	this->last = self->last[args[0]->b_edev];
+	this->dist = (int)(args[0]->b_blkno - this->last) > 0 ?
+	    args[0]->b_blkno - this->last : this->last - args[0]->b_blkno;
+
+	/* store details */
+	@Size[pid, curpsinfo->pr_psargs] = quantize(this->dist);
+}
+
+io:genunix::start
+{
+	/* save last position of disk head */
+	self->last[args[0]->b_edev] = args[0]->b_blkno +
+	    args[0]->b_bcount / 512;
+}
+
+/*
+ * Print final report
+ */
+dtrace:::END
+{
+	printf("\n%8s  %s\n", "PID", "CMD");
+	printa("%8d  %S\n%@d\n", @Size);
+}