From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752231AbcGFCQ3 (ORCPT ); Tue, 5 Jul 2016 22:16:29 -0400 Received: from mail-lf0-f43.google.com ([209.85.215.43]:36327 "EHLO mail-lf0-f43.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751339AbcGFCQ0 (ORCPT ); Tue, 5 Jul 2016 22:16:26 -0400 From: Marcin Wojtas To: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, netdev@vger.kernel.org Cc: davem@davemloft.net, linux@arm.linux.org.uk, sebastian.hesselbarth@gmail.com, andrew@lunn.ch, jason@lakedaemon.net, thomas.petazzoni@free-electrons.com, gregory.clement@free-electrons.com, nadavh@marvell.com, alior@marvell.com, nitroshift@yahoo.com, mw@semihalf.com, jaz@semihalf.com, Dmitri Epshtein , Subject: [PATCH net] net: mvneta: set real interrupt per packet for tx_done Date: Wed, 6 Jul 2016 04:18:58 +0200 Message-Id: <1467771538-31811-1-git-send-email-mw@semihalf.com> X-Mailer: git-send-email 1.8.3.1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Dmitri Epshtein 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 Cc: # v3.10+ Fixes aebea2ba0f74 ("net: mvneta: fix Tx interrupt delay") --- 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 cf04c97..0ad2fa3 100644 --- a/drivers/net/ethernet/marvell/mvneta.c +++ b/drivers/net/ethernet/marvell/mvneta.c @@ -244,7 +244,7 @@ /* 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 -- 1.8.3.1