From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755488AbcHSHMB (ORCPT ); Fri, 19 Aug 2016 03:12:01 -0400 Received: from mx2.suse.de ([195.135.220.15]:49811 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755021AbcHSHLz (ORCPT ); Fri, 19 Aug 2016 03:11:55 -0400 X-Amavis-Alert: BAD HEADER SECTION, Duplicate header field: "References" From: Jiri Slaby To: stable@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Dmitri Epshtein , Marcin Wojtas , "David S . Miller" , Jiri Slaby Subject: [PATCH 3.12 045/100] net: mvneta: set real interrupt per packet for tx_done Date: Fri, 19 Aug 2016 09:10:44 +0200 Message-Id: <547ce110cf46273e2cd526b03dfb7e9798375f33.1471589700.git.jslaby@suse.cz> X-Mailer: git-send-email 2.9.3 In-Reply-To: References: In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Dmitri Epshtein 3.12-stable review patch. If anyone has any objections, please let me know. =============== commit 06708f81528725148473c0869d6af5f809c6824b upstream. Commit aebea2ba0f74 ("net: mvneta: fix Tx interrupt delay") intended to set coalescing threshold to a value guaranteeing interrupt generation per each sent packet, so that buffers can be released with no delay. In fact setting threshold to '1' was wrong, because it causes interrupt every two packets. According to the documentation a reason behind it is following - interrupt occurs once sent buffers counter reaches a value, which is higher than one specified in MVNETA_TXQ_SIZE_REG(q). This behavior was confirmed during tests. Also when testing the SoC working as a NAS device, better performance was observed with int-per-packet, as it strongly depends on the fact that all transmitted packets are released immediately. This commit enables NETA controller work in interrupt per sent packet mode by setting coalescing threshold to 0. Signed-off-by: Dmitri Epshtein Signed-off-by: Marcin Wojtas Fixes aebea2ba0f74 ("net: mvneta: fix Tx interrupt delay") Acked-by: Willy Tarreau Signed-off-by: David S. Miller Signed-off-by: Jiri Slaby --- drivers/net/ethernet/marvell/mvneta.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/net/ethernet/marvell/mvneta.c b/drivers/net/ethernet/marvell/mvneta.c index 5902e6a93167..8c07b331ef58 100644 --- a/drivers/net/ethernet/marvell/mvneta.c +++ b/drivers/net/ethernet/marvell/mvneta.c @@ -212,7 +212,7 @@ /* Various constants */ /* Coalescing */ -#define MVNETA_TXDONE_COAL_PKTS 1 +#define MVNETA_TXDONE_COAL_PKTS 0 /* interrupt per packet */ #define MVNETA_RX_COAL_PKTS 32 #define MVNETA_RX_COAL_USEC 100 -- 2.9.3