From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Dumazet Subject: Re: [PATCH] loopback: better handling of packet drops Date: Fri, 17 Apr 2009 14:22:30 +0200 Message-ID: <49E87486.7090901@cosmosbay.com> References: <49E84B99.1080502@cosmosbay.com> <49E854A4.1010204@cosmosbay.com> <49E85AFD.6080407@cosmosbay.com> <20090417.035112.171173490.davem@davemloft.net> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: netdev@vger.kernel.org To: David Miller Return-path: Received: from gw1.cosmosbay.com ([212.99.114.194]:57478 "EHLO gw1.cosmosbay.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753384AbZDQMWi convert rfc822-to-8bit (ORCPT ); Fri, 17 Apr 2009 08:22:38 -0400 In-Reply-To: <20090417.035112.171173490.davem@davemloft.net> Sender: netdev-owner@vger.kernel.org List-ID: David Miller a =E9crit : > From: Eric Dumazet > Date: Fri, 17 Apr 2009 12:33:33 +0200 >=20 >> Splitting netif_rx() with a helper function boosts tbench >> performance by 1%, because we can avoid two tests (about netpoll and >> timestamping) >=20 > Loopback is not a special device no matter how much you wish > it might be :-) >=20 > This is why I haven't really pursued any further those patches I > showed you that treat local TCP connections specially, it just had th= e > realy possibility to break clever things people might be doing over > loopback using the packet scheduler classifier and packet scheduler > actions. Point taken. >=20 > I also think it is valid to use netpoll over loopback, especially for > testing. Oh I didnt knew it was possible/useful, sorry about that. >=20 > So please undo this part of the patch. You always try to combine > multiple distinct changes, and I would have taken just your TX drop > change if you hadn't added this __netif_rx() stuff to it :-( I followed on this patch to show what I had in mind, and why I thought it was a transmit error more than a receive one. 1) Do you reject idea of splitting netif_rx() to be able to not freeing skb in case of congestion ? 2) If not, do you want me to send two separate patches ? 3) Should I update rx_errors or tx_errors or both ? Thank you