From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ursula Braun Subject: [PATCH net 5/7] qeth: do not limit number of gso segments Date: Thu, 15 Sep 2016 14:39:25 +0200 Message-ID: <20160915123927.86579-6-ubraun@linux.vnet.ibm.com> References: <20160915123927.86579-1-ubraun@linux.vnet.ibm.com> Cc: netdev@vger.kernel.org, linux-s390@vger.kernel.org, schwidefsky@de.ibm.com, heiko.carstens@de.ibm.com, ubraun@linux.vnet.ibm.com To: davem@davemloft.net Return-path: Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:51720 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934250AbcIOMjk (ORCPT ); Thu, 15 Sep 2016 08:39:40 -0400 Received: from pps.filterd (m0098410.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.17/8.16.0.17) with SMTP id u8FCX8fq086421 for ; Thu, 15 Sep 2016 08:39:39 -0400 Received: from e06smtp07.uk.ibm.com (e06smtp07.uk.ibm.com [195.75.94.103]) by mx0a-001b2d01.pphosted.com with ESMTP id 25fr7xuw9r-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Thu, 15 Sep 2016 08:39:39 -0400 Received: from localhost by e06smtp07.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Thu, 15 Sep 2016 13:39:36 +0100 In-Reply-To: <20160915123927.86579-1-ubraun@linux.vnet.ibm.com> Sender: netdev-owner@vger.kernel.org List-ID: To reduce the need of skb_linearize() calls, gso_max_segs of qeth net_devices had been limited according to the maximum number of qdio SBAL elements. But a gso segment cannot be larger than the mtu-size, while an SBAL element can contain up to 4096 bytes. The gso_max_segs limitation limits the maximum packet size given to the qeth driver. Performance measurements with tso-enabled qeth network interfaces and mtu-size 1500 showed, that the disadvantage of smaller packets is much more severe than the advantage of fewer skb_linearize() calls. This patch gets rid of the gso_max_segs limitations in the qeth driver. Signed-off-by: Ursula Braun Reviewed-by: Thomas Richter --- drivers/s390/net/qeth_l2_main.c | 1 - drivers/s390/net/qeth_l3_main.c | 1 - 2 files changed, 2 deletions(-) diff --git a/drivers/s390/net/qeth_l2_main.c b/drivers/s390/net/qeth_l2_main.c index 54fd891..2081c18 100644 --- a/drivers/s390/net/qeth_l2_main.c +++ b/drivers/s390/net/qeth_l2_main.c @@ -1131,7 +1131,6 @@ static int qeth_l2_setup_netdev(struct qeth_card *card) qeth_l2_request_initial_mac(card); card->dev->gso_max_size = (QETH_MAX_BUFFER_ELEMENTS(card) - 1) * PAGE_SIZE; - card->dev->gso_max_segs = (QETH_MAX_BUFFER_ELEMENTS(card) - 1); SET_NETDEV_DEV(card->dev, &card->gdev->dev); netif_napi_add(card->dev, &card->napi, qeth_l2_poll, QETH_NAPI_WEIGHT); netif_carrier_off(card->dev); diff --git a/drivers/s390/net/qeth_l3_main.c b/drivers/s390/net/qeth_l3_main.c index 4ba82e1..0cbbc80 100644 --- a/drivers/s390/net/qeth_l3_main.c +++ b/drivers/s390/net/qeth_l3_main.c @@ -3148,7 +3148,6 @@ static int qeth_l3_setup_netdev(struct qeth_card *card) netif_keep_dst(card->dev); card->dev->gso_max_size = (QETH_MAX_BUFFER_ELEMENTS(card) - 1) * PAGE_SIZE; - card->dev->gso_max_segs = (QETH_MAX_BUFFER_ELEMENTS(card) - 1); SET_NETDEV_DEV(card->dev, &card->gdev->dev); netif_napi_add(card->dev, &card->napi, qeth_l3_poll, QETH_NAPI_WEIGHT); -- 2.8.4