From patchwork Mon Sep 28 19:03:27 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Honnappa Nagarahalli X-Patchwork-Id: 313678 Delivered-To: patch@linaro.org Received: by 2002:a92:5ad1:0:0:0:0:0 with SMTP id b78csp3545074ilg; Mon, 28 Sep 2020 12:04:12 -0700 (PDT) X-Google-Smtp-Source: ABdhPJwJkatQC3nZOkQkbfuB0DaHceLAti9wukAQvbqSq4pzLMr0AwKZBytgNkIYE9eFiqEg1kcz X-Received: by 2002:a50:9dc8:: with SMTP id l8mr3467146edk.58.1601319852792; Mon, 28 Sep 2020 12:04:12 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1601319852; cv=none; d=google.com; s=arc-20160816; b=BTMZ8s9fu5pOxCzKFOv+iMk2ZuDsPyinEX+obv6xMdRuSjTvuyB8TGDlVrcpGekT+Q R09kXOXJqnBqj1JPsbddR+fgtZpc2VPFlpZw/ybHDd6kvY2XtySUVWil1HuBVyFdiri/ Kgb4OTAufNoriPdgB65Kn0wdqOxifnp4oI8efTejiqnCWprtaXJIAV5Ou79gxI7xL4Iw /NS1ySEHOzQmh8BLYaLUMqCmtzMS9HgL/KF2KpVGOTBNEo3HeCGyQnpKSeJD0VOc5eFS NYv5C2iO5drlYACSY23RhvHsmjTzAemi8THdSw19+3k2m2MZ410TL2J1luc6s2TKVp/v Rq9g== 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=vOeJz8MfK06tflfpTWoaYWZkMyJOfJOy8ZSdAi+HTM0=; b=yREN2/F5W3S9VYn5JuCdENrTkFw7PW/dIt4siyprXp5vENLCtsakgxh/hcpb+wq4Ri wis1RV3ImQf+En6oX+m7WwdyR/tqN337D1mijOHsPr7bQPcNxkNtCG8Gy6f5rxnYp1LF G5dp6PrmjQRbswcTI6XWmWbqOZq0FsNYuG+0iB8lMa7MtUdU9UA7n62jNLVt9aod67xW J6lk+g+DuMR3vRZUyx5XGK7WIK2a9ChN+MOKPkaVNsl1HLOb1l+GKI8j4PF5APKL/SdN thN5F9l1DH1ZrGxlMKSpFDNJyGjUGWxM87gFLg7TxCK3MH/Ga4DYUKPHZJRhuGmyyMfi Bzww== 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 qn11si1182800ejb.303.2020.09.28.12.04.12; Mon, 28 Sep 2020 12:04:12 -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 529AE1D614; Mon, 28 Sep 2020 21:04:05 +0200 (CEST) Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by dpdk.org (Postfix) with ESMTP id 978201D553; Mon, 28 Sep 2020 21:04:02 +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 F0E371063; Mon, 28 Sep 2020 12:04:00 -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 DBADB3F70D; Mon, 28 Sep 2020 12:04:00 -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, 28 Sep 2020 14:03:27 -0500 Message-Id: <20200928190334.40624-1-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 v2 1/8] 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 Reviewed-by: Ruifeng Wang --- drivers/net/memif/rte_eth_memif.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) -- 2.17.1 Reviewed-by: Jakub Grajciar diff --git a/drivers/net/memif/rte_eth_memif.c b/drivers/net/memif/rte_eth_memif.c index a19c0f3e6..130099f2e 100644 --- a/drivers/net/memif/rte_eth_memif.c +++ b/drivers/net/memif/rte_eth_memif.c @@ -580,12 +580,10 @@ 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;