From owner-freebsd-stable@FreeBSD.ORG Wed May 11 15:11:34 2005 Return-Path: Delivered-To: freebsd-stable@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 270BF16A4D0 for ; Wed, 11 May 2005 15:11:34 +0000 (GMT) Received: from rproxy.gmail.com (rproxy.gmail.com [64.233.170.196]) by mx1.FreeBSD.org (Postfix) with ESMTP id 71BE643D58 for ; Wed, 11 May 2005 15:11:33 +0000 (GMT) (envelope-from subhro.kar@gmail.com) Received: by rproxy.gmail.com with SMTP id j1so105900rnf for ; Wed, 11 May 2005 08:11:33 -0700 (PDT) DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=beta; d=gmail.com; h=received:message-id:date:from:organization:user-agent:x-accept-language:mime-version:to:cc:subject:references:in-reply-to:content-type; b=s/tUBmXTA5ZCkAH1EO5q2lwf68OBUolm5WiuDUkdS7noK5IOVhprhU9LXC04oiKFRwgI1EJ24hWk7a/g8pp0daqJJCTsxIKPpulGZzTIPL/HnTmUyRbMl3qnL8HlvpIpoxwo619EGkCgLgpOiS22TUUlz4SfrAwNGQOV28UuTaM= Received: by 10.38.14.38 with SMTP id 38mr128181rnn; Wed, 11 May 2005 08:11:33 -0700 (PDT) Received: from ?59.93.160.192? ([59.93.160.192]) by mx.gmail.com with ESMTP id 70sm123481rnb.2005.05.11.08.11.30; Wed, 11 May 2005 08:11:33 -0700 (PDT) Message-ID: <4282209C.3070507@gmail.com> Date: Wed, 11 May 2005 20:41:24 +0530 From: Subhro Organization: Indian Institute of Information Technology User-Agent: Mozilla Thunderbird 1.0.2 (Windows/20050317) X-Accept-Language: en-us, en MIME-Version: 1.0 To: Tuomo Latto References: <20050511051016.93990.qmail@web54002.mail.yahoo.com> <42819770.9070007@gmail.com> <4281C1FC.800@mbnet.fi> In-Reply-To: <4281C1FC.800@mbnet.fi> Content-Type: multipart/mixed; boundary="------------050305000602040908090708" X-Content-Filtered-By: Mailman/MimeDel 2.1.1 cc: FreeBSD current cc: FreeBSD Stable Subject: Re: xl(4) & polling X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 11 May 2005 15:11:34 -0000 This is a multi-part message in MIME format. --------------050305000602040908090708 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit On 5/11/2005 13:57, Tuomo Latto wrote: > Subhro wrote: > ... > >> In Device Polled systems, the NIC does not generate any interrupt at >> all. Instead whenever the packets arrive at a Network interface, they >> are captured and put into a queue. The kernel scheduler checks the >> quese at regular intervals and processes the packets which are >> waiting. This interval is adjusted by the "options HZ=x" kernel option. >> >> If the value of x is very high, there may eb two scenarios. In the >> first scenario, the queue may fill up and subsequent packets are >> dropped. In this case retransmission of the packets are required. In >> the second scenario, the packets would be held up for excessive long >> times which defeats the entire purpose of Device Polling. If the >> value of x is very low, the scheduler would check the queue >> frequently and would again defeat the entire idea of Device Polling. > > > It's the other way around. Large values indicate larger polling frequency > thus amounting to more checks. Or at least the name of the option would > suggest that anyway. > > Silly me :(. I meant something, typed something else. Its indeed the other way round. Thanks to everyone who pointed this out. Regards S. --------------050305000602040908090708--