From mboxrd@z Thu Jan 1 00:00:00 1970 From: linas@austin.ibm.com (Linas Vepstas) Subject: [PATCH 17/18] spidernet: turn off descriptor chain end interrupt. Date: Thu, 7 Jun 2007 15:01:52 -0500 Message-ID: <20070607200152.GQ16077@austin.ibm.com> References: <20070607191707.GA7904@austin.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: cbe-oss-dev@ozlabs.org, netdev@vger.kernel.org, Nathan J Lee , Ling Shao , Utz Bacher , Zhen Bo Zhu , Zhu Han , Jens Osterkamp , Yan Qi Wang To: Jeff Garzik Return-path: Received: from e6.ny.us.ibm.com ([32.97.182.146]:50807 "EHLO e6.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933246AbXFGUBy (ORCPT ); Thu, 7 Jun 2007 16:01:54 -0400 Received: from d01relay02.pok.ibm.com (d01relay02.pok.ibm.com [9.56.227.234]) by e6.ny.us.ibm.com (8.13.8/8.13.8) with ESMTP id l57K2wfP028975 for ; Thu, 7 Jun 2007 16:02:58 -0400 Received: from d01av03.pok.ibm.com (d01av03.pok.ibm.com [9.56.224.217]) by d01relay02.pok.ibm.com (8.13.8/8.13.8/NCO v8.3) with ESMTP id l57K1rpj493316 for ; Thu, 7 Jun 2007 16:01:53 -0400 Received: from d01av03.pok.ibm.com (loopback [127.0.0.1]) by d01av03.pok.ibm.com (8.12.11.20060308/8.13.3) with ESMTP id l57K1qr1006984 for ; Thu, 7 Jun 2007 16:01:53 -0400 Content-Disposition: inline In-Reply-To: <20070607191707.GA7904@austin.ibm.com> Sender: netdev-owner@vger.kernel.org List-Id: netdev.vger.kernel.org At some point, the transmit descriptor chain end interrupt (TXDCEINT) was turned on. This is a mistake; and it damages small packet transmit performance, as it results in a huge storm of interrupts. Turn it off. Signed-off-by: Linas Vepstas ---- drivers/net/spider_net.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) Index: linux-2.6.22-rc1/drivers/net/spider_net.h =================================================================== --- linux-2.6.22-rc1.orig/drivers/net/spider_net.h 2007-06-07 11:56:31.000000000 -0500 +++ linux-2.6.22-rc1/drivers/net/spider_net.h 2007-06-07 11:56:36.000000000 -0500 @@ -227,6 +227,7 @@ extern char spider_net_driver_name[]; #define SPIDER_NET_GDTBSTA 0x00000300 #define SPIDER_NET_GDTDCEIDIS 0x00000002 #define SPIDER_NET_DMA_TX_VALUE SPIDER_NET_TX_DMA_EN | \ + SPIDER_NET_GDTDCEIDIS | \ SPIDER_NET_GDTBSTA #define SPIDER_NET_DMA_TX_FEND_VALUE 0x00030003 @@ -337,8 +338,7 @@ enum spider_net_int2_status { SPIDER_NET_GRISPDNGINT }; -#define SPIDER_NET_TXINT ( (1 << SPIDER_NET_GDTFDCINT) | \ - (1 << SPIDER_NET_GDTDCEINT) ) +#define SPIDER_NET_TXINT (1 << SPIDER_NET_GDTFDCINT) /* We rely on flagged descriptor interrupts */ #define SPIDER_NET_RXINT ( (1 << SPIDER_NET_GDAFDCINT) )