From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bill Fink Subject: Re: sendfile()? Re: SO_LINGER dead: I get an immediate RST on 2.6.24? Date: Tue, 13 Jan 2009 01:56:14 -0500 Message-ID: <20090113015614.3b815ad7.billfink@mindspring.com> References: <20090113063205.GA26047@gondor.apana.org.au> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: ilpo.jarvinen@helsinki.fi, zbr@ioremap.net, bert.hubert@netherlabs.nl, h.willstrand@gmail.com, netdev@vger.kernel.org To: Herbert Xu Return-path: Received: from elasmtp-curtail.atl.sa.earthlink.net ([209.86.89.64]:60103 "EHLO elasmtp-curtail.atl.sa.earthlink.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750953AbZAMG40 (ORCPT ); Tue, 13 Jan 2009 01:56:26 -0500 In-Reply-To: <20090113063205.GA26047@gondor.apana.org.au> Sender: netdev-owner@vger.kernel.org List-ID: On Tue, 13 Jan 2009, Herbert Xu wrote: > Bill Fink wrote: > > > > If I understand you correctly, to hit this corner case, just after > > the final TCP write, there would have to be no packets in flight > > together with a zero TCP window. To make it more bullet-proof, I > > guess after seeing a zero tcpi_unacked, an additional small delay > > should be performed, and then rechecking for a zero tcpi_unacked. > > I don't see anything else obvious (to me anyway) in the tcp_info > > that would be particularly helpful in handling this. > > What's wrong with idiag_wqueue? Isn't that a much more direct > way to get this? I'm not familiar with idiag_wqueue, but it sounds like it has something to do with INET_DIAG/INET_TCP_DIAG. It was a long time ago, but I seem to recall that using INET_DIAG had a negative impact on performance, and since the main point of nuttcp is to measure TCP/UDP performance, that would be contrary to its primary purpose. Also, I don't want to rely on something that's not guaranteed to be part of the running kernel. -Bill