From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [PATCH net-next 2/3] mlx4_en: moderate frequency of TX completions Date: Thu, 23 Feb 2012 16:46:42 -0500 (EST) Message-ID: <20120223.164642.1510847570351068406.davem@davemloft.net> References: <4F464063.1010001@mellanox.co.il> <20120223.144437.32389814881687535.davem@davemloft.net> <1330031636.2511.13.camel@bwh-desktop> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: yevgenyp@mellanox.co.il, netdev@vger.kernel.org To: bhutchings@solarflare.com Return-path: Received: from shards.monkeyblade.net ([198.137.202.13]:56681 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752288Ab2BWVqw (ORCPT ); Thu, 23 Feb 2012 16:46:52 -0500 In-Reply-To: <1330031636.2511.13.camel@bwh-desktop> Sender: netdev-owner@vger.kernel.org List-ID: From: Ben Hutchings Date: Thu, 23 Feb 2012 21:13:56 +0000 > On Thu, 2012-02-23 at 14:44 -0500, David Miller wrote: >> From: Yevgeny Petrilin >> Date: Thu, 23 Feb 2012 15:34:27 +0200 >> >> > No need to ask for completion for every packet being sent. >> > So the method is to ask for a completion every 16 packets, >> > or when the queue is about to be full. >> > >> > Signed-off-by: Yevgeny Petrilin >> >> You absolutely cannot do this, you must signal completion and free up >> TX queue packets in a finite amount of time. > > Really, sfc has been doing this forever. You have to stop, because otherwise sockets can hang since those packets can hold a reference to the socket so they must be released in a finite amount of time regardless of network traffic.