#!/usr/sbin/dtrace -s
/*
* dnlcsnoop.d - snoop DNLC activity.
* Written in DTrace (Solaris 10 3/05).
*
* The DNLC is the Directory Name Lookup Cache. Filename lookups often
* return a hit from here, before needing to traverse the regular file
* system cache or go to disk.
*
* 20-Apr-2006, ver 0.71
*
*
* USAGE: dnlcsnoop.d # wait several seconds, then hit Ctrl-C
*
* FIELDS:
* PID Process ID
* CMD Command name
* TIME Elapsed time for lookup, us
* HIT DNLC hit Y/N
* PATH Path for DNLC lookup
*
* 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
*
* 27-Mar-2004 Brendan Gregg Created this.
* 14-Jun-2005 " " Rewrote this a lot.
*/
#pragma D option quiet
/*
* Print header
*/
dtrace:::BEGIN
{
printf("%6s %-12s %5s %3s %s\n",
"PID", "CMD", "TIME", "HIT", "PATH");
}
/*
* DNLC lookup
*/
fbt:genunix:dnlc_lookup:entry
{
/* store path */
self->path = stringof(args[0]->v_path);
/* check for trailing "/" */
this->len = strlen(self->path);
self->join = *(char *)(args[0]->v_path + this->len - 1) == '/' ?
"" : "/";
/* store lookup name */
self->name = stringof(arg1);
/* store start time */
self->start = timestamp;
}
/*
* DNLC return
*/
fbt:genunix:dnlc_lookup:return
/self->start/
{
/* calculate elapsed time */
this->elapsed = (timestamp - self->start) / 1000;
/* print output */
printf("%6d %-12.12s %5d %3s %s%s%s\n",
pid, execname, this->elapsed, arg1 == 0 ? "N" : "Y",
self->path, self->join, self->name);
/* clear variables */
self->path = 0;
self->join = 0;
self->name = 0;
self->start = 0;
}