#!/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,v 1.1.1.1 2015/09/30 22:01:07 christos Exp $ * * 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); }