From owner-freebsd-net Mon Nov 19 1: 2:23 2001 Delivered-To: freebsd-net@freebsd.org Received: from iguana.aciri.org (iguana.aciri.org [192.150.187.36]) by hub.freebsd.org (Postfix) with ESMTP id 543DA37B405 for ; Mon, 19 Nov 2001 01:02:21 -0800 (PST) Received: (from rizzo@localhost) by iguana.aciri.org (8.11.3/8.11.1) id fAJ8w6B09815; Mon, 19 Nov 2001 00:58:06 -0800 (PST) (envelope-from rizzo) Date: Mon, 19 Nov 2001 00:58:06 -0800 From: Luigi Rizzo To: Vladimir Girnetz Cc: net@FreeBSD.ORG Subject: Re: ipfw + pipes Message-ID: <20011119005806.A9378@iguana.aciri.org> References: <20011119104807.D70300-100000@ns.moldnet.md> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20011119104807.D70300-100000@ns.moldnet.md> User-Agent: Mutt/1.3.23i Sender: owner-freebsd-net@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.org On Mon, Nov 19, 2001 at 10:49:11AM +0200, Vladimir Girnetz wrote: > Hi > > How many pipes can be created under FreeBSD 4.4? as many as 64k independent pipes, each of which can have a large number (default 1k, but can be soft-configurable) of dynamic pipes. So essentially it is limited by the available RAM. > How the number of pipes will be reflected on usage of CPU and RAM? space is linear in the total number of pipes, per packet processing time is in the worst case logarithmic in the number of active pipes (i.e. those with backlogged traffic). But basically, for most practical applications the performance hit will go unnoticed, and even with the most complex configurations I wouldn't expect a slowdown of more than a factor of 2. [and i hear screams in the background from people who think "oh no, for my application more than 1% overhead is unacceptable" to whom i suggest to run "top" in a window, quickly move the mouse around, and enjoy the "interrupt" stats going up...] cheers luigi ----------------------------------+----------------------------------------- Luigi RIZZO, luigi@iet.unipi.it . ACIRI/ICSI (on leave from Univ. di Pisa) http://www.iet.unipi.it/~luigi/ . 1947 Center St, Berkeley CA 94704 Phone: (510) 666 2927 ----------------------------------+----------------------------------------- To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message