From mboxrd@z Thu Jan 1 00:00:00 1970 From: Florian Westphal Subject: Re: [PATCH -next] net: tcp: add mib counters to track zero window transitions Date: Wed, 19 Feb 2014 20:18:31 +0100 Message-ID: <20140219191831.GA7119@breakpoint.cc> References: <1392674268-26005-1-git-send-email-fw@strlen.de> <20140219.131708.562226572566677127.davem@davemloft.net> <1392835787.18849.11.camel@edumazet-glaptop2.roam.corp.google.com> <20140219185949.GA1179@order.stressinduktion.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii To: Eric Dumazet , David Miller , netdev@vger.kernel.org Return-path: Received: from Chamillionaire.breakpoint.cc ([80.244.247.6]:33552 "EHLO Chamillionaire.breakpoint.cc" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754724AbaBSTSf (ORCPT ); Wed, 19 Feb 2014 14:18:35 -0500 Content-Disposition: inline In-Reply-To: <20140219185949.GA1179@order.stressinduktion.org> Sender: netdev-owner@vger.kernel.org List-ID: Hannes Frederic Sowa wrote: > On Wed, Feb 19, 2014 at 10:49:47AM -0800, Eric Dumazet wrote: > > On Wed, 2014-02-19 at 13:17 -0500, David Miller wrote: > > > From: Florian Westphal > > > Date: Mon, 17 Feb 2014 22:57:48 +0100 > > > > > > > Three counters are added: > > > > - one to track when we went from non-zero to zero window > > > > - one to track the reverse > > > > - one counter incremented when we want to announce zero window. > > > > > > > > The latter is added because it can show cases where we want to close the > > > > window but can't because we would shrink window. > > > > > > > > Suggested-by: Eric Dumazet > > > > Signed-off-by: Florian Westphal > > > > --- > > > > Eric, is this what you had in mind? > > > > > > > > I re-ran my 'slow-sender-with-reader-that-does-not-drain-socket' > > > > scenario and, as expected, only TCPWANTZEROWINDOW increases. > > > > > > Eric, ping? > > > > Thanks, I missed this patch. Let me think about it, thanks ! > > We need NET_INC_STATS instead of NET_INC_STATS_BH, no? sure, I can send v2 but I'll wait for (n)ack from Eric first before considering it. tcp_transmit_skb (caller of tcp_select_window) also uses _BH which is why it ended up in tcp_select_window.