#!/usr/sbin/dtrace -s
 /*
  * hotspot.d - plot disk event by location, look for hotspots.
  *             Written in DTrace (Solaris 10 3/05).
  *
  * This simple DTrace script determines if disk activity is occuring in
  * the one place - a "hotspot". This helps us understand the system's usage
  * of a disk, it does not imply that the existance or not of a hotspot is
  * good or bad (often may be good, less seeking).
  *
  * $Id: hotspot.d 3 2007-08-01 10:50:08Z brendan $
  *
  * USAGE:       hotspot.d       # hit Ctrl-C to end
  *
  * FIELDS:
  *              Disk            disk instance name
  *              Major           driver major number
  *              Minor           driver minor number
  *              value           location, by megabyte
  *              count           number of I/O operations
  *
  * COPYRIGHT: Copyright (c) 2005, 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
  *
  * 07-May-2005	Brendan Gregg	Created this.
  * 20-Apr-2006	   "      "	Last update.
  */
 
 #pragma D option quiet
 
 inline int DISK_MB_MAX = 1000000;	/* max size of a single disk */
 inline int REPORT_SCALE_MB = 1000;	/* output step size for report */
 
 /*
  * Print header
  */
 dtrace:::BEGIN
 {
 	printf("Tracing... Hit Ctrl-C to end.\n");
 }
 
 /*
  * Process disk event
  */
 io:::start
 {
 	this->mb = args[0]->b_blkno / 2048;
 	@Block[args[1]->dev_statname, args[1]->dev_major, args[1]->dev_minor] =
 	    lquantize(this->mb, 0, DISK_MB_MAX, REPORT_SCALE_MB);
 }
 
 /*
  * Print final report
  */
 dtrace:::END
 {
 	printa("Disk: %s   Major,Minor: %d,%d\n%@d\n", @Block);
 }