From owner-freebsd-hackers@FreeBSD.ORG Mon Jun 27 21:17:37 2005 Return-Path: X-Original-To: freebsd-hackers@freebsd.org Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 01B6D16A41C for ; Mon, 27 Jun 2005 21:17:37 +0000 (GMT) (envelope-from samuel.pierson@gmail.com) Received: from wproxy.gmail.com (wproxy.gmail.com [64.233.184.197]) by mx1.FreeBSD.org (Postfix) with ESMTP id 957FD43D49 for ; Mon, 27 Jun 2005 21:17:36 +0000 (GMT) (envelope-from samuel.pierson@gmail.com) Received: by wproxy.gmail.com with SMTP id 57so484154wri for ; Mon, 27 Jun 2005 14:17:36 -0700 (PDT) DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=beta; d=gmail.com; h=received:message-id:date:from:reply-to:to:subject:mime-version:content-type:content-transfer-encoding:content-disposition; b=Jf29B6Fi9Y7tuG6TwKCGwPvxU8YtAfCW48AAobYmNsOiS5bTQ91HLnLDTQnXH6eXwgtm01uxaOQBvQ0rEnQ4OVi1HV0v/H5lTbDtGSmM2a71Myj0tacq7mD5k4yp1GgEJzKhYAjXIgF23+bIpKD/Shf2eaNs4PCmz7gnO52ZkPw= Received: by 10.54.67.3 with SMTP id p3mr3743148wra; Mon, 27 Jun 2005 14:17:35 -0700 (PDT) Received: by 10.54.144.1 with HTTP; Mon, 27 Jun 2005 14:17:34 -0700 (PDT) Message-ID: Date: Mon, 27 Jun 2005 16:17:34 -0500 From: Sam Pierson To: FreeBSD Hackers Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Content-Disposition: inline Subject: Accurate/Fine-grained timing of latency in atheros drivers X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list Reply-To: Sam Pierson List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 27 Jun 2005 21:17:37 -0000 Hey guys, In a current project, I need to find out exactly how long it takes to send a 802.11 packet and how much time is spent in the following stages: send time - time spent constructing message, including context switches and other delays and the time it takes to transfer the message to the network card. access time - delay which we experience waiting to access the transmitting channel. Normally this would include the RTS and CTS queuing signals, but for this application, I have to disable them. Is it possible that no t= ime is spent waiting here, if I have disabled the whole CSMA scheme on the hardware level? propagation time - how long it takes to get to the receiver, once it has le= ft our card receive time - how long it takes for the receiving network card to get the= =20 message and notify the host that it has something to read. Am I going to have to put in hardware interrupts to time these events or=20 are such tools already available? =20 -Sam