From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ursula Braun Subject: [PATCH net 1/3] net/smc: optimize consumer cursor updates Date: Wed, 18 Jul 2018 14:06:21 +0200 Message-ID: <20180718120621.66413-1-ubraun@linux.ibm.com> Cc: netdev@vger.kernel.org, linux-s390@vger.kernel.org, schwidefsky@de.ibm.com, heiko.carstens@de.ibm.com, raspl@linux.ibm.com, linux-kernel@vger.kernel.org To: davem@davemloft.net Return-path: Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:39476 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729281AbeGRMoK (ORCPT ); Wed, 18 Jul 2018 08:44:10 -0400 Received: from pps.filterd (m0098409.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.22/8.16.0.22) with SMTP id w6IBxQYV144935 for ; Wed, 18 Jul 2018 08:06:33 -0400 Received: from e06smtp03.uk.ibm.com (e06smtp03.uk.ibm.com [195.75.94.99]) by mx0a-001b2d01.pphosted.com with ESMTP id 2ka3cgn3rr-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Wed, 18 Jul 2018 08:06:32 -0400 Received: from localhost by e06smtp03.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Wed, 18 Jul 2018 13:06:30 +0100 Sender: netdev-owner@vger.kernel.org List-ID: From: Ursula Braun The SMC protocol requires to send a separate consumer cursor update, if it cannot be piggybacked to updates of the producer cursor. Currently the decision to send a separate consumer cursor update just considers the amount of data already received by the socket program. It does not consider the amount of data already arrived, but not yet consumed by the receiver. Basing the decision on the difference between already confirmed and already arrived data (instead of difference between already confirmed and already consumed data), may lead to a somewhat earlier consumer cursor update send in fast unidirectional traffic scenarios, and thus to better throughput. Signed-off-by: Ursula Braun Suggested-by: Thomas Richter --- net/smc/smc_tx.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/net/smc/smc_tx.c b/net/smc/smc_tx.c index cee666400752..f82886b7d1d8 100644 --- a/net/smc/smc_tx.c +++ b/net/smc/smc_tx.c @@ -495,7 +495,8 @@ void smc_tx_work(struct work_struct *work) void smc_tx_consumer_update(struct smc_connection *conn, bool force) { - union smc_host_cursor cfed, cons; + union smc_host_cursor cfed, cons, prod; + int sender_free = conn->rmb_desc->len; int to_confirm; smc_curs_write(&cons, @@ -505,11 +506,18 @@ void smc_tx_consumer_update(struct smc_connection *conn, bool force) smc_curs_read(&conn->rx_curs_confirmed, conn), conn); to_confirm = smc_curs_diff(conn->rmb_desc->len, &cfed, &cons); + if (to_confirm > conn->rmbe_update_limit) { + smc_curs_write(&prod, + smc_curs_read(&conn->local_rx_ctrl.prod, conn), + conn); + sender_free = conn->rmb_desc->len - + smc_curs_diff(conn->rmb_desc->len, &prod, &cfed); + } if (conn->local_rx_ctrl.prod_flags.cons_curs_upd_req || force || ((to_confirm > conn->rmbe_update_limit) && - ((to_confirm > (conn->rmb_desc->len / 2)) || + ((sender_free <= (conn->rmb_desc->len / 2)) || conn->local_rx_ctrl.prod_flags.write_blocked))) { if ((smc_cdc_get_slot_and_msg_send(conn) < 0) && conn->alert_token_local) { /* connection healthy */ -- 2.16.4