From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753386AbdBCNlw (ORCPT ); Fri, 3 Feb 2017 08:41:52 -0500 Received: from mail-wm0-f66.google.com ([74.125.82.66]:34512 "EHLO mail-wm0-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752208AbdBCNlu (ORCPT ); Fri, 3 Feb 2017 08:41:50 -0500 Date: Fri, 3 Feb 2017 14:41:45 +0100 From: Corentin Labbe To: David Miller Cc: peppe.cavallaro@st.com, alexandre.torgue@st.com, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 13/17] net: stmmac: Implement NAPI for TX Message-ID: <20170203134145.GB3653@Red> References: <20170131091152.13842-1-clabbe.montjoie@gmail.com> <20170131091152.13842-14-clabbe.montjoie@gmail.com> <20170131.231225.59679013563845652.davem@davemloft.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170131.231225.59679013563845652.davem@davemloft.net> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jan 31, 2017 at 11:12:25PM -0500, David Miller wrote: > From: Corentin Labbe > Date: Tue, 31 Jan 2017 10:11:48 +0100 > > > The stmmac driver run TX completion under NAPI but without checking > > the work done by the TX completion function. > > The current behavior is correct and completely intentional. > > A driver should _never_ account TX work to the NAPI poll budget. > > This is because TX liberation is orders of magnitude cheaper than > receiving a packet, and such SKB freeing makes more SKBs available > for RX processing. > > Therefore, TX work should never count against the NAPI budget. > > Please do not fix something which is not broken. So at least the documentation I read must be fixed (https://wiki.linuxfoundation.org/networking/napi) So perhaps the best way is to do like intel igb/ixgbe, keeping under NAPI until the stmmac_tx_clean function said that it finish handling the queue ? Regards Corentin Labbe