From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Dumazet Subject: RE: [PATCH 0/2] Tracepoint for tcp retransmission Date: Wed, 21 Dec 2011 08:05:11 +0100 Message-ID: <1324451111.2610.13.camel@edumazet-laptop> References: <65795E11DBF1E645A09CEC7EAEE94B9CB5AFA64F@USINDEVS02.corp.hds.com> <5f654c7d-f18e-4d70-8830-a3e31b8f5f4a@tahiti.vyatta.com> <20111218004944.GB14903@hell> <65795E11DBF1E645A09CEC7EAEE94B9CB5AFB01E@USINDEVS02.corp.hds.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: Hagen Paul Pfeifer , Stephen Hemminger , "nhorman@tuxdriver.com" , "davem@davemloft.net" , "tgraf@infradead.org" , Seiji Aguchi , "dle-develop@lists.sourceforge.net" , "netdev@vger.kernel.org" To: Satoru Moriya Return-path: Received: from mail-ww0-f44.google.com ([74.125.82.44]:59557 "EHLO mail-ww0-f44.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752324Ab1LUHFa (ORCPT ); Wed, 21 Dec 2011 02:05:30 -0500 Received: by wgbdr13 with SMTP id dr13so13758922wgb.1 for ; Tue, 20 Dec 2011 23:05:29 -0800 (PST) In-Reply-To: <65795E11DBF1E645A09CEC7EAEE94B9CB5AFB01E@USINDEVS02.corp.hds.com> Sender: netdev-owner@vger.kernel.org List-ID: Le mardi 20 d=C3=A9cembre 2011 =C3=A0 18:40 -0500, Satoru Moriya a =C3=A9= crit : > We use trace_kfree_skb() which 63e03724b51 uses to detect packet > drop event. In addition to that, we would like to detect errors > in TCP layer for better trouble shooting. >=20 If you feel we miss a counter in a particular spot, just add it, so tha= t even a newbie can report "netstat -s" values in a message for analysis. Not re-sending a frame because of a temporary shortage of memory is not an error per se, TCP will recover eventually, but keeping track of thes= e events might be useful (once we have not percpu counters for this, but regular atomic counters)