From owner-freebsd-questions@FreeBSD.ORG Fri Oct 20 08:18:02 2006 Return-Path: X-Original-To: freebsd-questions@freebsd.org Delivered-To: freebsd-questions@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 6F27916A415 for ; Fri, 20 Oct 2006 08:18:02 +0000 (UTC) (envelope-from ke.han@redstarling.com) Received: from smtp102.biz.mail.re2.yahoo.com (smtp102.biz.mail.re2.yahoo.com [68.142.229.216]) by mx1.FreeBSD.org (Postfix) with SMTP id AD4E743D77 for ; Fri, 20 Oct 2006 08:17:57 +0000 (GMT) (envelope-from ke.han@redstarling.com) Received: (qmail 78873 invoked from network); 20 Oct 2006 08:17:57 -0000 Received: from unknown (HELO ?192.168.1.20?) (ke.han@redstarling.com@218.79.209.77 with plain) by smtp102.biz.mail.re2.yahoo.com with SMTP; 20 Oct 2006 08:17:56 -0000 In-Reply-To: <20061020080526.GA23594@lakshmi.susmita.org> References: <20061020080526.GA23594@lakshmi.susmita.org> Mime-Version: 1.0 (Apple Message framework v752.3) Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed Message-Id: Content-Transfer-Encoding: 7bit From: ke han Date: Fri, 20 Oct 2006 16:17:52 +0800 To: girishvenkatachalam@gmail.com X-Mailer: Apple Mail (2.752.3) Cc: freebsd-questions Questions list Subject: Re: FreeBSD 6.1 max sockets X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 20 Oct 2006 08:18:02 -0000 Thanks for the reply. This app is intended to keep 20,000++ sockets alive at a time. These sockets are very long lived. I understand about kqueue. I will eventually write for this. What I need to understand are the various kernel tunings required to handle 20,000++ active sockets. I would like to approach the theoretical max...is it 64k? That is, is the absolute max socket descriptors 64k? any thing else in the way of this maximum? thanks, ke han On Oct 20, 2006, at 4:05 PM, Girish Venkatachalam wrote: > On Thu, Oct 19, 2006 at 11:24:30PM +0800, ke han wrote: >> I am writing a socket server deamon in C++ on FreeBSD 6.1 (or 6.2 if >> this matters to your answer). What this does is accept many sockets >> and does a little work with each. Each socket has low traffic but >> stay connected for long periods. All these sockets get accepted >> through one public ip:port (if this matters). >> So my desire is two things: >> 1 - good event handling for knowing which sockets have new data. I >> assume kqueue is the way to go here? >> 2 - I need to know what my limits are on max number of sockets. If >> my system is a 64-bit install on a server with 8GB RAM, I need to >> know how many sockets I can handle. Also, what options do I have to >> tune this? socket buffer size? Any kernel parameters needed to >> tune? >> > As Chuck said select(2) is a good choice. That is what I used. > kqueue() is more powerful and certainly much better when it comes > to handling large number of sockets since kqueue(2) is very > efficient when it comes to polling sockets for events. > > If you use select, the problem is that if you have say 2000 sockets > and only one socket is available for read/write, then select has a > stupid algo to figure out. Doesn't scale well. > > But kqueue(2) is very good at that sort of thing. Also kqueue() has > a built in event mechanism that can be extended for signals and > files also. > > If the sockets stay connected for long periods you may also want to > enable TCP KEEPALIVE flag on the sockets. > > I don't think RAM and processor will be the bottleneck for you. > > Since in typical scenarios number of concurrent connected sockets > don't usually hit such high limits. > > They come and go... > > HTH. > > Best of luck! > > regards, > Girish > _______________________________________________ > freebsd-questions@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-questions > To unsubscribe, send any mail to "freebsd-questions- > unsubscribe@freebsd.org"