#!/usr/sbin/dtrace -s
/*
* weblatency.d - website latency statistics.
* Written using DTrace (Solaris 10 3/05).
*
* 20-Apr-2006, ver 0.61 (early release)
*
* USAGE: weblatency.d # hit Ctrl-C to end sample
*
* See the code below for the "BROWSER" variable, which sets the browser
* to trace (currently set to "mozilla-bin").
*
* This is written as an experimental tool, and may not work at all with
* your browser.
*
* FIELDS:
* HOST Hostname from URL
* NUM Number of GETs
* AVGTIME(ms) Average time for response, ms
* MAXTIME(ms) Maximum time for response, ms
*
* NOTE:
*
* The latency measured here is from the browser sending the GET
* request to when the browser begins to recieve the response. It
* is an overall response time for the client, and encompasses
* connection speed delays, DNS lookups, proxy delays, and web server
* response time.
*
* IDEA: Bryan Cantrill (who wrote an elegant version for Sol 10 update 1)
*
* 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
*
* ToDo:
* Check write fd for socket, not file.
*
* 30-Nov-2005 Brendan Gregg Created this.
*/
#pragma D option quiet
/* browser's execname */
inline string BROWSER = "Safari";
/* maximum expected hostname length + "GET http://" */
inline int MAX_REQ = 64;
dtrace:::BEGIN
{
printf("Tracing... Hit Ctrl-C to end.\n");
}
/*
* Trace brower request
*
* This is achieved by matching writes for the browser's execname that
* start with "GET", and then timing from the return of the write to
* the return of the next read in the same thread. Various stateful flags
* are used: self->fd, self->read.
*
* For performance reasons, I'd like to only process writes that follow a
* connect(), however this approach fails to process keepalives.
*/
syscall::write_nocancel:entry,
syscall::write:entry
/execname == BROWSER/
{
self->buf = arg1;
self->fd = arg0 + 1;
self->nam = "";
}
syscall::write_nocancel:return,
syscall::write:return
/self->fd/
{
this->str = (char *)copyin(self->buf, MAX_REQ);
this->str[4] = '\0';
self->fd = stringof(this->str) == "GET " ? self->fd : 0;
}
syscall::write_nocancel:return,
syscall::write:return
/self->fd/
{
/* fetch browser request */
this->str = (char *)copyin(self->buf, MAX_REQ);
this->str[MAX_REQ] = '\0';
self->nam = strtok(&(this->str[4])," ?");
/* start the timer */
start[pid, self->fd - 1] = timestamp;
host[pid, self->fd - 1] = self->nam;
self->buf = 0;
self->fd = 0;
self->req = 0;
self->nam = 0;
}
/* this one wasn't a GET */
syscall::write_nocancel:return,
syscall::write:return
/self->buf/
{
self->buf = 0;
self->fd = 0;
}
syscall::read_nocancel:entry,
syscall::read:entry
/execname == BROWSER && start[pid, arg0]/
{
self->fd = arg0 + 1;
}
/*
* Record host details
*/
syscall::read_nocancel:return,
syscall::read:return
/self->fd/
{
/* fetch details */
self->host = stringof(host[pid, self->fd - 1]);
this->start = start[pid, self->fd - 1];
/* save details */
@Avg[self->host] = avg((timestamp - this->start)/1000000);
@Max[self->host] = max((timestamp - this->start)/1000000);
@Num[self->host] = count();
/* clear vars */
start[pid, self->fd - 1] = 0;
host[pid, self->fd - 1] = 0;
self->host = 0;
self->fd = 0;
}
/*
* Output report
*/
dtrace:::END
{
printf("%-32s %11s\n", "HOST", "NUM");
printa("%-32s %@11d\n", @Num);
printf("\n%-32s %11s\n", "HOST", "AVGTIME(ms)");
printa("%-32s %@11d\n", @Avg);
printf("\n%-32s %11s\n", "HOST", "MAXTIME(ms)");
printa("%-32s %@11d\n", @Max);
}