From owner-freebsd-fs@FreeBSD.ORG  Fri Nov  4 13:58:50 2011
Return-Path: <owner-freebsd-fs@FreeBSD.ORG>
Delivered-To: freebsd-fs@freebsd.org
Received: by hub.freebsd.org (Postfix, from userid 1233)
	id DA231106566C; Fri,  4 Nov 2011 13:58:50 +0000 (UTC)
Date: Fri, 4 Nov 2011 13:58:50 +0000
From: Alexander Best <arundel@freebsd.org>
To: freebsd-fs@freebsd.org
Message-ID: <20111104135850.GA25559@freebsd.org>
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
Subject: tmpfs(5) speeds
X-BeenThere: freebsd-fs@freebsd.org
X-Mailman-Version: 2.1.5
Precedence: list
List-Id: Filesystems <freebsd-fs.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-fs>,
	<mailto:freebsd-fs-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-fs>
List-Post: <mailto:freebsd-fs@freebsd.org>
List-Help: <mailto:freebsd-fs-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-fs>,
	<mailto:freebsd-fs-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Fri, 04 Nov 2011 13:58:50 -0000

hi there,

using 'time dd if=/dev/zero of=/tmp/test bs=1m count=500' i got a result of:

500+0 records in
500+0 records out
524288000 bytes transferred in 1.133749 secs (462437450 bytes/sec)
dd if=/dev/zero of=/tmp/test bs=1m count=500  0,00s user 1,33s system 99% cpu 1,332 total

isn't this a bit slow? i've seen people get speeds of 2 gigabytes/sec
running striped SSDs as fs backend.

the RAM i'm using is 2x1GB DDR2 non-ECC memory 800MHZ (PC2-6400) and CL4 (4-4-4-12).

http://en.wikipedia.org/wiki/DDR2_SDRAM shows a peek 6400 megabyte/sec.

i'm running HEAD on amd64.

cheers.
alex