From mboxrd@z Thu Jan 1 00:00:00 1970 From: Giuseppe CAVALLARO Subject: Re: [net-next.git 4/7] stmmac: add Rx watchdog optimization to mitigate the DMA irqs Date: Thu, 06 Sep 2012 08:06:14 +0200 Message-ID: <50483D56.1020208@st.com> References: <1346857432-24657-1-git-send-email-peppe.cavallaro@st.com> <1346857432-24657-5-git-send-email-peppe.cavallaro@st.com> <1346861675.5325.13.camel@bwh-desktop.uk.solarflarecom.com> <20120905.131615.1131246696009291033.davem@davemloft.net> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: bhutchings@solarflare.com, netdev@vger.kernel.org To: David Miller Return-path: Received: from eu1sys200aog118.obsmtp.com ([207.126.144.145]:56918 "EHLO eu1sys200aog118.obsmtp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751301Ab2IFGGd (ORCPT ); Thu, 6 Sep 2012 02:06:33 -0400 In-Reply-To: <20120905.131615.1131246696009291033.davem@davemloft.net> Sender: netdev-owner@vger.kernel.org List-ID: On 9/5/2012 7:16 PM, David Miller wrote: > From: Ben Hutchings > Date: Wed, 5 Sep 2012 17:14:35 +0100 > >> On Wed, 2012-09-05 at 17:03 +0200, Giuseppe CAVALLARO wrote: >>> GMAC devices newer than databook 3.50 has an embedded timer >>> that can be used for mitigating the number of interrupts. >>> So this patch adds this optimizations. >>> Old MAC will continue to use NAPI. >> [...] >> >> Interrupt moderation is *not* a substitute for NAPI; you should continue >> using NAPI as well. > > Absolutely correct, these two facilities are _complementary_ not _exlusive_. > > In fact, the most optimal driver will use NAPI with relatively short HW > mitigation settings. > David, Ben, many thanks for your notes and review. I'll apply them and re-test the driver using NAPI plus the HW wdt feature. Regards Peppe