From patchwork Mon Sep 21 19:22:51 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Honnappa Nagarahalli X-Patchwork-Id: 313401 Delivered-To: patch@linaro.org Received: by 2002:a92:5ad1:0:0:0:0:0 with SMTP id b78csp3821870ilg; Mon, 21 Sep 2020 12:23:14 -0700 (PDT) X-Google-Smtp-Source: ABdhPJyXSNkXXKD+crWgOmn1dzrDmD/VJ0hA7KvbgQqBGCPY0LRWfWKyVxNeJ1FaraDX0T9mArCm X-Received: by 2002:a17:906:b74c:: with SMTP id fx12mr956176ejb.547.1600716194240; Mon, 21 Sep 2020 12:23:14 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1600716194; cv=none; d=google.com; s=arc-20160816; b=pzaVj7BWgfeuuLBjt10+tFa1Q+/xyMKUUQMZny7Vu0rJjbpWybFQaHRteJ4XTVFs7Z HQwH07BvODos6n8ZKLyc8P85mV9xxn4rv/fvVZrSIciGPVwJfNLvs7FJEFomfaOEsKxq thT46fdRs5o/yeN7hCdMQuGdjX+I5pCeBAfz6A1cpBCl6gNuzlwLEIBbAMXweYCtyXkN jw2p1+ch/dymIl+ykllIZmc2bFJ3jhuO2MBTP7b9/L1OXj7COM03GZsfmf1pNOT1FHrn 4boKVjTscpKLCz2RFNUlOi8XW/w6jh7fGdWQTBJLEXhNnq52ERQn9h4WWJDkV1m2tvG+ XB+w== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=sender:errors-to:list-subscribe:list-help:list-post:list-archive :list-unsubscribe:list-id:precedence:subject:message-id:date:cc:to :from; bh=4TdyMiDDBwsxoyHgJvqPVUlFBkgvgir3Cxdbq/mjJm8=; b=EAFiGY7AoIUqpNQ4C4tOsNPX3UAEtYNoEcUzuB0tV2oJtRs+xPcF6pVtMqwpO7MwMv V9Z79QXgPjW9qzMFtkBNVYsBkCcD+AHht+xxW7iuLH8BvDI56386RZ3gXzqju8qKtEpY 8mGP4S9WVf+rgexsIvon1d4lU7WeNPN/k37VvwMN+aK/2BKuJ+PB4uszq3cbLc0h3Qay kvwPav9giHLPYc1z/ER/iwCovvmn9vOT895uC2EtGw+Bpt0sL5gbdCnqRWGLWqZ32aPW YrD+zPogQ2aaDH4qpKcRPgTq/2EGG6cEIGJ9c1+hMEIPT5eA8oaZuodsqMF5ofJ3Gx62 q/UA== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of dev-bounces@dpdk.org designates 92.243.14.124 as permitted sender) smtp.mailfrom=dev-bounces@dpdk.org Return-Path: Received: from dpdk.org (dpdk.org. [92.243.14.124]) by mx.google.com with ESMTP id i88si9723479edd.601.2020.09.21.12.23.14; Mon, 21 Sep 2020 12:23:14 -0700 (PDT) Received-SPF: pass (google.com: domain of dev-bounces@dpdk.org designates 92.243.14.124 as permitted sender) client-ip=92.243.14.124; Authentication-Results: mx.google.com; spf=pass (google.com: domain of dev-bounces@dpdk.org designates 92.243.14.124 as permitted sender) smtp.mailfrom=dev-bounces@dpdk.org Received: from [92.243.14.124] (localhost [127.0.0.1]) by dpdk.org (Postfix) with ESMTP id 484D31D977; Mon, 21 Sep 2020 21:23:13 +0200 (CEST) Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by dpdk.org (Postfix) with ESMTP id 7B3B21D94B; Mon, 21 Sep 2020 21:23:11 +0200 (CEST) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id BD5411045; Mon, 21 Sep 2020 12:23:09 -0700 (PDT) Received: from qc2400f-1.austin.arm.com (qc2400f-1.austin.arm.com [10.118.12.27]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id AC1E43F718; Mon, 21 Sep 2020 12:23:09 -0700 (PDT) From: Honnappa Nagarahalli To: dev@dpdk.org, honnappa.nagarahalli@arm.com, phil.yang@arm.com, jgrajcia@cisco.com, ferruh.yigit@intel.com Cc: nd@arm.com, stable@dpdk.org Date: Mon, 21 Sep 2020 14:22:51 -0500 Message-Id: <20200921192254.20560-1-honnappa.nagarahalli@arm.com> X-Mailer: git-send-email 2.17.1 Subject: [dpdk-dev] [PATCH 1/4] net/memif: do not update local copy of tail in tx function X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" In the case of S2M queues, the receiver synchronizes with the sender (i.e. informs of the packets it has received) using ring->tail. Hence, the sender does not need to update last_tail. In the case of M2S queues, the receiver uses last_tail to keep track of the descriptors it has received. The sender is not required to update the last_tail. Updating the last_tail makes it a shared variable between the transmitter and receiver affecting the performance. Fixes: 09c7e63a71f9 ("net/memif: introduce memory interface PMD") Cc: jgrajcia@cisco.com Cc: stable@dpdk.org Signed-off-by: Honnappa Nagarahalli Reviewed-by: Phil Yang --- drivers/net/memif/rte_eth_memif.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) -- 2.17.1 diff --git a/drivers/net/memif/rte_eth_memif.c b/drivers/net/memif/rte_eth_memif.c index c1c7e9f8d..fd7dbc53e 100644 --- a/drivers/net/memif/rte_eth_memif.c +++ b/drivers/net/memif/rte_eth_memif.c @@ -568,12 +568,10 @@ eth_memif_tx(void *queue, struct rte_mbuf **bufs, uint16_t nb_pkts) ring_size = 1 << mq->log2_ring_size; mask = ring_size - 1; - n_free = __atomic_load_n(&ring->tail, __ATOMIC_ACQUIRE) - mq->last_tail; - mq->last_tail += n_free; - if (type == MEMIF_RING_S2M) { slot = __atomic_load_n(&ring->head, __ATOMIC_ACQUIRE); - n_free = ring_size - slot + mq->last_tail; + n_free = ring_size - slot + + __atomic_load_n(&ring->tail, __ATOMIC_ACQUIRE); } else { slot = __atomic_load_n(&ring->tail, __ATOMIC_ACQUIRE); n_free = __atomic_load_n(&ring->head, __ATOMIC_ACQUIRE) - slot; From patchwork Mon Sep 21 19:22:52 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Honnappa Nagarahalli X-Patchwork-Id: 313402 Delivered-To: patch@linaro.org Received: by 2002:a92:5ad1:0:0:0:0:0 with SMTP id b78csp3821956ilg; Mon, 21 Sep 2020 12:23:21 -0700 (PDT) X-Google-Smtp-Source: ABdhPJwxegAnT9+O/9C1b4uLUrK08PUg+CTPDVAb6FTfPnAYSAs81xioHMioYUYYT3U4OOh+qXFo X-Received: by 2002:a05:6402:3076:: with SMTP id bs22mr457933edb.17.1600716201790; Mon, 21 Sep 2020 12:23:21 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1600716201; cv=none; d=google.com; s=arc-20160816; b=RnGFy2JL2I8juFOLtYpnuK2JJ7gd+ZZyqz1YrHNaO/I1ZtuoJ7F3iNKzOlYjuT87eX NsaxwVOzwLUzWZv8+WSSfC86etJ6jlB19NMgqtxFFnAA6uyOQJNxZ1omSwz9WGQsOFJF g25qyPYaImQwXrKmowTOCyq1tyU81UGGmzrAobPvyMo8uTxKqSTdP89zp+9GQkcA/hso 4sHBhczhzyQo/xubbUxjPirOMUL0sTSCUj2uca5eDpA4AmRRP3FGmSmkCbaQ8u/z9W8U Mq6epKb6xsSsYt67vaGvyDXrrgAG4uXJaUT9j4jPb67KShRcHlswKvM2tEtzwHGi1xYz YhbQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=sender:errors-to:list-subscribe:list-help:list-post:list-archive :list-unsubscribe:list-id:precedence:subject:references:in-reply-to :message-id:date:cc:to:from; bh=d/LhEQT0cIZp9REXQsZptyhwBX3iPeTPE0Ga7xFkG5s=; b=Kqg4bLvNzN5MnGII/SdWjGj0KDtmkRVewuLcDK51UKCuN0C+XlS6sKFNK44UljACzY LgRFMMNd361mz/ZtkjyKVQDIjSDXoze/gv3xl5L/5U1WxkEDssusGKavxp5dMRF/f6YJ XqT78K+c5JL1W05LjrkpDgE8vBikKm95qTbNvwi6Uy1mPQEh5pgK33Y6qIMNbZoQgYV6 7cq8kuyPsl9rYoUmC3XLnVB243HI/MJVo6/jd+kYRpKdyt5eRvvzVK6INe8M9gc7Tjp8 I2Ww66wR7eaZ35Do8HP6XUfY3ZuttkNx4z5xx2JUmDPQ0c13H3bCHmprvG7s4A7PnyB2 4pzQ== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of dev-bounces@dpdk.org designates 92.243.14.124 as permitted sender) smtp.mailfrom=dev-bounces@dpdk.org Return-Path: Received: from dpdk.org (dpdk.org. [92.243.14.124]) by mx.google.com with ESMTP id pg2si8912374ejb.328.2020.09.21.12.23.21; Mon, 21 Sep 2020 12:23:21 -0700 (PDT) Received-SPF: pass (google.com: domain of dev-bounces@dpdk.org designates 92.243.14.124 as permitted sender) client-ip=92.243.14.124; Authentication-Results: mx.google.com; spf=pass (google.com: domain of dev-bounces@dpdk.org designates 92.243.14.124 as permitted sender) smtp.mailfrom=dev-bounces@dpdk.org Received: from [92.243.14.124] (localhost [127.0.0.1]) by dpdk.org (Postfix) with ESMTP id 1F2BC1DA54; Mon, 21 Sep 2020 21:23:16 +0200 (CEST) Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by dpdk.org (Postfix) with ESMTP id AF2AA1D94B; Mon, 21 Sep 2020 21:23:12 +0200 (CEST) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id F41291045; Mon, 21 Sep 2020 12:23:11 -0700 (PDT) Received: from qc2400f-1.austin.arm.com (qc2400f-1.austin.arm.com [10.118.12.27]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id E3D513F718; Mon, 21 Sep 2020 12:23:11 -0700 (PDT) From: Honnappa Nagarahalli To: dev@dpdk.org, honnappa.nagarahalli@arm.com, phil.yang@arm.com, jgrajcia@cisco.com, ferruh.yigit@intel.com Cc: nd@arm.com, stable@dpdk.org Date: Mon, 21 Sep 2020 14:22:52 -0500 Message-Id: <20200921192254.20560-2-honnappa.nagarahalli@arm.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200921192254.20560-1-honnappa.nagarahalli@arm.com> References: <20200921192254.20560-1-honnappa.nagarahalli@arm.com> Subject: [dpdk-dev] [PATCH 2/4] net/memif: relax the load of ring tail pointer for M2S ring X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" For M2S rings, ring->tail is updated by the sender and eth_memif_tx function is called in the context of sending thread. The loads in the sender do not need to synchronize with its own stores. Fixes: a2aafb9aa651 ("net/memif: optimize with one-way barrier") Cc: phil.yang@arm.com Cc: stable@dpdk.org Signed-off-by: Honnappa Nagarahalli Reviewed-by: Phil Yang --- drivers/net/memif/rte_eth_memif.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) -- 2.17.1 diff --git a/drivers/net/memif/rte_eth_memif.c b/drivers/net/memif/rte_eth_memif.c index fd7dbc53e..0d064c8fa 100644 --- a/drivers/net/memif/rte_eth_memif.c +++ b/drivers/net/memif/rte_eth_memif.c @@ -573,7 +573,13 @@ eth_memif_tx(void *queue, struct rte_mbuf **bufs, uint16_t nb_pkts) n_free = ring_size - slot + __atomic_load_n(&ring->tail, __ATOMIC_ACQUIRE); } else { - slot = __atomic_load_n(&ring->tail, __ATOMIC_ACQUIRE); + /* For M2S queues ring->tail is updated by the sender and + * this function is called in the context of sending thread. + * The loads in the sender do not need to synchronize with + * its own stores. Hence, the following load can be a + * relaxed load. + */ + slot = __atomic_load_n(&ring->tail, __ATOMIC_RELAXED); n_free = __atomic_load_n(&ring->head, __ATOMIC_ACQUIRE) - slot; } From patchwork Mon Sep 21 19:22:53 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Honnappa Nagarahalli X-Patchwork-Id: 313403 Delivered-To: patch@linaro.org Received: by 2002:a92:5ad1:0:0:0:0:0 with SMTP id b78csp3822057ilg; Mon, 21 Sep 2020 12:23:29 -0700 (PDT) X-Google-Smtp-Source: ABdhPJxZtG2S+1cEuhwBG5YywBd7Wc3Ew4xpyNfvVAwQL5q35pAUIPHaZxF/YgNUULnibsUcZuvi X-Received: by 2002:a05:6402:3105:: with SMTP id dc5mr447574edb.105.1600716209627; Mon, 21 Sep 2020 12:23:29 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1600716209; cv=none; d=google.com; s=arc-20160816; b=OOtCV+MkZ0hiJkzqZIfEk7td+HcO92z9rEFGwf/Xe8rZEj3nYQ1+NJDLrip1rFoNj9 QwfFU5T2z4UPPQg4B2nMOSY7r2M6XiFE3xho3ezbeUNYP8tiDmujP4jbThK9cs7zyKmq e138YLE4eDPL4K+AY4Nrb6twtSH2Aopzi7WTABuhwz+fyqfbQMEuvJN7+gL01Qnxci7R K5+FIfb4WjZ99rIYz3pvVGWko/aEMIfQjGxM0oscoZEPnM8545PlbETU2zCi2uxfTFLD OjeLvDUaTZQdCxSYge4pHC79XApxXRv3uIF3UTU0By9XdCJDk0AJi3PEUpE/SkpA3oLx LN7Q== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=sender:errors-to:list-subscribe:list-help:list-post:list-archive :list-unsubscribe:list-id:precedence:subject:references:in-reply-to :message-id:date:cc:to:from; bh=t1ySOYB4skjTE0Zv4MJt5hCqmd5l2SyuddKHXDW7zKE=; b=vj/5h4xwqvebFrEifscupXBg9XieJOpHjhqY2NK+9Y1OEoEjNgnyIpVa924f1FTOTS gwGCFiEMOB3K6IudkzxnGEC1svYTlhTXxQZvotTwmw7KBtCTPtQS6k+mOhN0MriNlO5C 9hhZ0qBQwSQ/FGjSmz8xbMXp4y0apN4Fp4Gxf1TLNalXKsjtnNTSYOuDFXMJ9SKqm132 kr1OdVoTHOp20soqWji7JwCr/Jv+hteCNoUFTqOQyLz47M3YxRBZeIfb+tmbzldOXxtR 8bZOF+6juucXuhi5MmwnkvpQmvB8WBkz8aibKxlaMj465aswSXFoG2pbCNBwQ8uaElOj xqVA== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of dev-bounces@dpdk.org designates 92.243.14.124 as permitted sender) smtp.mailfrom=dev-bounces@dpdk.org Return-Path: Received: from dpdk.org (dpdk.org. [92.243.14.124]) by mx.google.com with ESMTP id a3si4025503edn.245.2020.09.21.12.23.29; Mon, 21 Sep 2020 12:23:29 -0700 (PDT) Received-SPF: pass (google.com: domain of dev-bounces@dpdk.org designates 92.243.14.124 as permitted sender) client-ip=92.243.14.124; Authentication-Results: mx.google.com; spf=pass (google.com: domain of dev-bounces@dpdk.org designates 92.243.14.124 as permitted sender) smtp.mailfrom=dev-bounces@dpdk.org Received: from [92.243.14.124] (localhost [127.0.0.1]) by dpdk.org (Postfix) with ESMTP id B01F51DA64; Mon, 21 Sep 2020 21:23:17 +0200 (CEST) Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by dpdk.org (Postfix) with ESMTP id 5F0891D993; Mon, 21 Sep 2020 21:23:13 +0200 (CEST) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id E085214F6; Mon, 21 Sep 2020 12:23:12 -0700 (PDT) Received: from qc2400f-1.austin.arm.com (qc2400f-1.austin.arm.com [10.118.12.27]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id D07663F718; Mon, 21 Sep 2020 12:23:12 -0700 (PDT) From: Honnappa Nagarahalli To: dev@dpdk.org, honnappa.nagarahalli@arm.com, phil.yang@arm.com, jgrajcia@cisco.com, ferruh.yigit@intel.com Cc: nd@arm.com, stable@dpdk.org Date: Mon, 21 Sep 2020 14:22:53 -0500 Message-Id: <20200921192254.20560-3-honnappa.nagarahalli@arm.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200921192254.20560-1-honnappa.nagarahalli@arm.com> References: <20200921192254.20560-1-honnappa.nagarahalli@arm.com> Subject: [dpdk-dev] [PATCH 3/4] net/memif: relax the load of ring head pointer for S2M ring X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" For S2M rings, ring->head is updated by the sender and eth_memif_tx function is called in the context of sending thread. The loads in the sender do not need to synchronize with its own stores. Fixes: a2aafb9aa651 ("net/memif: optimize with one-way barrier") Cc: phil.yang@arm.com Cc: stable@dpdk.org Signed-off-by: Honnappa Nagarahalli Reviewed-by: Phil Yang --- drivers/net/memif/rte_eth_memif.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) -- 2.17.1 diff --git a/drivers/net/memif/rte_eth_memif.c b/drivers/net/memif/rte_eth_memif.c index 0d064c8fa..435c6345c 100644 --- a/drivers/net/memif/rte_eth_memif.c +++ b/drivers/net/memif/rte_eth_memif.c @@ -569,7 +569,13 @@ eth_memif_tx(void *queue, struct rte_mbuf **bufs, uint16_t nb_pkts) mask = ring_size - 1; if (type == MEMIF_RING_S2M) { - slot = __atomic_load_n(&ring->head, __ATOMIC_ACQUIRE); + /* For S2M queues ring->head is updated by the sender and + * this function is called in the context of sending thread. + * The loads in the sender do not need to synchronize with + * its own stores. Hence, the following load can be a + * relaxed load. + */ + slot = __atomic_load_n(&ring->head, __ATOMIC_RELAXED); n_free = ring_size - slot + __atomic_load_n(&ring->tail, __ATOMIC_ACQUIRE); } else { From patchwork Mon Sep 21 19:22:54 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Honnappa Nagarahalli X-Patchwork-Id: 313404 Delivered-To: patch@linaro.org Received: by 2002:a92:5ad1:0:0:0:0:0 with SMTP id b78csp3822132ilg; Mon, 21 Sep 2020 12:23:37 -0700 (PDT) X-Google-Smtp-Source: ABdhPJwQwHUusGlit8UOOtk+IxNucbEF6HMk5TC7YUBX7RcaM9vB8KMo1aUevfo3gYY/fgdOzN9T X-Received: by 2002:aa7:c61a:: with SMTP id h26mr451379edq.254.1600716217416; Mon, 21 Sep 2020 12:23:37 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1600716217; cv=none; d=google.com; s=arc-20160816; b=vbLI2RPRH8Pwv0e55yDd1Rklb5uILCuMM9TcUpzgj2hTcZrJ2XOyJVDkhFu9KGAiR/ 6fFHFsYCGyph5fjkp2CeLez9S+pKEyCTAAE0yb7ygArjsqUbeSOXA7YiQAAwNDG4UJtB 7IBPwJOLWUm+4mTbnjoLSo1P65GRoQ2wIpLJ+z9rGEX36odwAM9NsRRSHsuF02GbkxkM LxYDYsrryjpSKmNa2RRwLh6aJ+sl7aKk1FgVhgrhTy8Fey9W4WrM1D8iEZiMTF0h9s6R 9+rtQU3KZ74c82MPbyyWNT5XYKCmmdzMZEiUtE4xOcAtxmBcKROzYEj0WvlCnYY7XzXK t6mQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=sender:errors-to:list-subscribe:list-help:list-post:list-archive :list-unsubscribe:list-id:precedence:subject:references:in-reply-to :message-id:date:cc:to:from; bh=SoIKEg5P3IK1liWOIeo+X7rfyJRjxz9I+kcWzV9Nhjs=; b=ZrS4AWCKcjHknMxCiTCwQMj0weIngK+kci9oQ793sxQipEEuzdMk1Ef+esW7UTaoFq pYftZ9VP7fpZ7hSGRG+BT2ySTLCk+RFyssQu18CFPdzXY3NqQX/RJdDz30kH6Uouw6/F 5jQOsBpvVhxdYaxOWtt/k9PX3tmBxcPJjRzoJG+9GK//TI8wryNBpAznZg4TT5p6O1Ed Kei3FKULuemQR7gc6lnV8BNcHi/dbkm0tJWwHGceh6mSec/yJfbvsU5My9oogYUNbUyB 6qpy1VCuEbqqg32lFQlgLGRaJJkiNeVXrQUMug50zrvzJokqa9CRl9keV1Sir9LtFq9i ZW3w== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of dev-bounces@dpdk.org designates 92.243.14.124 as permitted sender) smtp.mailfrom=dev-bounces@dpdk.org Return-Path: Received: from dpdk.org (dpdk.org. [92.243.14.124]) by mx.google.com with ESMTP id l25si8859475eje.688.2020.09.21.12.23.37; Mon, 21 Sep 2020 12:23:37 -0700 (PDT) Received-SPF: pass (google.com: domain of dev-bounces@dpdk.org designates 92.243.14.124 as permitted sender) client-ip=92.243.14.124; Authentication-Results: mx.google.com; spf=pass (google.com: domain of dev-bounces@dpdk.org designates 92.243.14.124 as permitted sender) smtp.mailfrom=dev-bounces@dpdk.org Received: from [92.243.14.124] (localhost [127.0.0.1]) by dpdk.org (Postfix) with ESMTP id 3CC641DA7D; Mon, 21 Sep 2020 21:23:19 +0200 (CEST) Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by dpdk.org (Postfix) with ESMTP id B181D1D9E2; Mon, 21 Sep 2020 21:23:14 +0200 (CEST) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 337F61045; Mon, 21 Sep 2020 12:23:14 -0700 (PDT) Received: from qc2400f-1.austin.arm.com (qc2400f-1.austin.arm.com [10.118.12.27]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 22FBC3F718; Mon, 21 Sep 2020 12:23:14 -0700 (PDT) From: Honnappa Nagarahalli To: dev@dpdk.org, honnappa.nagarahalli@arm.com, phil.yang@arm.com, jgrajcia@cisco.com, ferruh.yigit@intel.com Cc: nd@arm.com, stable@dpdk.org Date: Mon, 21 Sep 2020 14:22:54 -0500 Message-Id: <20200921192254.20560-4-honnappa.nagarahalli@arm.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200921192254.20560-1-honnappa.nagarahalli@arm.com> References: <20200921192254.20560-1-honnappa.nagarahalli@arm.com> Subject: [dpdk-dev] [PATCH 4/4] net/memif: relax the load of ring head pointer for M2S ring X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" For M2S rings, ring->head is updated by the receiver and eth_memif_rx function is called in the context of receiving thread. The loads in the sender do not need to synchronize with its own stores. Fixes: a2aafb9aa651 ("net/memif: optimize with one-way barrier") Cc: phil.yang@arm.com Cc: stable@dpdk.org Signed-off-by: Honnappa Nagarahalli Reviewed-by: Phil Yang --- drivers/net/memif/rte_eth_memif.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) -- 2.17.1 diff --git a/drivers/net/memif/rte_eth_memif.c b/drivers/net/memif/rte_eth_memif.c index 435c6345c..1cbb1fd7a 100644 --- a/drivers/net/memif/rte_eth_memif.c +++ b/drivers/net/memif/rte_eth_memif.c @@ -405,7 +405,11 @@ eth_memif_rx(void *queue, struct rte_mbuf **bufs, uint16_t nb_pkts) refill: if (type == MEMIF_RING_M2S) { - head = __atomic_load_n(&ring->head, __ATOMIC_ACQUIRE); + /* ring->head is updated by the receiver and this function + * is called in the context of receiver thread. The loads in + * the receiver do not need to synchronize with its own stores. + */ + head = __atomic_load_n(&ring->head, __ATOMIC_RELAXED); n_slots = ring_size - head + mq->last_tail; while (n_slots--) {