From owner-freebsd-hackers@FreeBSD.ORG Sat Mar 8 08:09:52 2008 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id C3C87106573B for ; Sat, 8 Mar 2008 08:09:52 +0000 (UTC) (envelope-from dudu@dudu.ro) Received: from fg-out-1718.google.com (fg-out-1718.google.com [72.14.220.157]) by mx1.freebsd.org (Postfix) with ESMTP id 610178FC16 for ; Sat, 8 Mar 2008 08:09:51 +0000 (UTC) (envelope-from dudu@dudu.ro) Received: by fg-out-1718.google.com with SMTP id 16so736598fgg.35 for ; Sat, 08 Mar 2008 00:09:51 -0800 (PST) Received: by 10.82.161.19 with SMTP id j19mr5739989bue.9.1204963787987; Sat, 08 Mar 2008 00:09:47 -0800 (PST) Received: by 10.82.185.8 with HTTP; Sat, 8 Mar 2008 00:09:47 -0800 (PST) Message-ID: Date: Sat, 8 Mar 2008 10:09:47 +0200 From: "Vlad GALU" To: "Robert Watson" In-Reply-To: <20080307223723.X42870@fledge.watson.org> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <20080307223723.X42870@fledge.watson.org> Cc: freebsd-hackers@freebsd.org Subject: Re: A (perhaps silly) kqueue question X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 08 Mar 2008 08:09:52 -0000 On 3/8/08, Robert Watson wrote: > On Fri, 7 Mar 2008, Vlad GALU wrote: > > > > I see an unusual symptom with one of our in-house applications. The main I/O > > loop calls kevent(), which in turn returns two events with EV_EOF error set, > > always for the same descriptors (they're both socket descriptors). As the > > man page is not pretty clear about it and I don't have my UNP copy at hand, > > I would like to ask the list whether the error events are supposed to be > > one-shot or not. > > > I wonder if it's returning one event for the read socket buffer, and one event > for the write socket buffer, since there are really two event sources for each > socket? Not that this is desirable behavior, but it might explain it. If you > shutdown() only read, do you get back one EOF kevent and one writable kevent? I'll try that and see. The only issue being the low frequency this symptom appears at. I'll get back to the list once I have more info. > > Robert N M Watson > Computer Laboratory > University of Cambridge > -- Mahnahmahnah!