From owner-freebsd-performance@FreeBSD.ORG  Fri Dec 22 01:49:57 2006
Return-Path: <owner-freebsd-performance@FreeBSD.ORG>
X-Original-To: freebsd-performance@freebsd.org
Delivered-To: freebsd-performance@freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52])
	by hub.freebsd.org (Postfix) with ESMTP id 323DA16A492
	for <freebsd-performance@freebsd.org>;
	Fri, 22 Dec 2006 01:49:57 +0000 (UTC)
	(envelope-from markir@paradise.net.nz)
Received: from smtp3.clear.net.nz (smtp3.clear.net.nz [203.97.33.64])
	by mx1.freebsd.org (Postfix) with ESMTP id E5D0113C457
	for <freebsd-performance@freebsd.org>;
	Fri, 22 Dec 2006 01:49:56 +0000 (UTC)
	(envelope-from markir@paradise.net.nz)
Received: from [192.168.1.11]
	(121-72-65-158.dsl.telstraclear.net [121.72.65.158])
	by smtp3.clear.net.nz (CLEAR Net Mail)
	with ESMTP id <0JAN00FSKJR6G730@smtp3.clear.net.nz> for
	freebsd-performance@freebsd.org; Fri, 22 Dec 2006 14:49:56 +1300 (NZDT)
Date: Fri, 22 Dec 2006 14:49:53 +1300
From: Mark Kirkwood <markir@paradise.net.nz>
In-reply-to: <458B3651.8090601@paradise.net.nz>
To: freebsd-performance@freebsd.org
Message-id: <458B39C1.2080906@paradise.net.nz>
MIME-version: 1.0
Content-type: multipart/mixed; boundary=------------050506000400060507050102
References: <458B3651.8090601@paradise.net.nz>
User-Agent: Thunderbird 1.5.0.8 (X11/20061129)
Subject: Re: Cached file read performance
X-BeenThere: freebsd-performance@freebsd.org
X-Mailman-Version: 2.1.5
Precedence: list
List-Id: Performance/tuning <freebsd-performance.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-performance>,
	<mailto:freebsd-performance-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-performance>
List-Post: <mailto:freebsd-performance@freebsd.org>
List-Help: <mailto:freebsd-performance-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-performance>,
	<mailto:freebsd-performance-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Fri, 22 Dec 2006 01:49:57 -0000

This is a multi-part message in MIME format.
--------------050506000400060507050102
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Content-Transfer-Encoding: 7bit

Mark Kirkwood wrote:

> Anyway on to the results: I used the attached program to read a cached 

Silly bug in attached program : lseek failure test has 1 instead of -1 
(finger trouble).

--------------050506000400060507050102
Content-Type: text/x-patch;
 name="readtest.c.patch"
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="readtest.c.patch"

*** readtest.c.orig	Fri Dec 22 14:43:42 2006
--- readtest.c	Fri Dec 22 14:43:24 2006
***************
*** 103,109 ****
  			}
  		} else {
  			offset = (off_t) (random() % (numblocks - 1)) * blocksz;
! 			if (lseek(fd, offset, SEEK_SET) == 1) {
  				perror("seek failed");
  				exit(1);
  			}
--- 103,109 ----
  			}
  		} else {
  			offset = (off_t) (random() % (numblocks - 1)) * blocksz;
! 			if (lseek(fd, offset, SEEK_SET) == -1) {
  				perror("seek failed");
  				exit(1);
  			}

--------------050506000400060507050102--