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/*
* 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 usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright 2005 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
#pragma D option quiet
io:::start
{
start[args[0]->b_edev, args[0]->b_blkno] = timestamp;
}
io:::done
/start[args[0]->b_edev, args[0]->b_blkno]/
{
/*
* We want to get an idea of our throughput to this device in KB/sec.
* What we have, however, is nanoseconds and bytes. That is we want
* to calculate:
*
* bytes / 1024
* ------------------------
* nanoseconds / 1000000000
*
* But we can't calculate this using integer arithmetic without losing
* precision (the denomenator, for one, is between 0 and 1 for nearly
* all I/Os). So we restate the fraction, and cancel:
*
* bytes 1000000000 bytes 976562
* --------- * ------------- = --------- * -------------
* 1024 nanoseconds 1 nanoseconds
*
* This is easy to calculate using integer arithmetic; this is what
* we do below.
*/
this->elapsed = timestamp - start[args[0]->b_edev, args[0]->b_blkno];
@[args[1]->dev_statname, args[1]->dev_pathname] =
quantize((args[0]->b_bcount * 976562) / this->elapsed);
start[args[0]->b_edev, args[0]->b_blkno] = 0;
}
END
{
printa(" %s (%s)\n%@d\n", @);
}
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