From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mails.dpdk.org (mails.dpdk.org [217.70.189.124]) by inbox.dpdk.org (Postfix) with ESMTP id AAF7AA00C2 for ; Fri, 17 Jun 2022 09:02:42 +0200 (CEST) Received: from [217.70.189.124] (localhost [127.0.0.1]) by mails.dpdk.org (Postfix) with ESMTP id A35FE41148; Fri, 17 Jun 2022 09:02:42 +0200 (CEST) Received: from mga01.intel.com (mga01.intel.com [192.55.52.88]) by mails.dpdk.org (Postfix) with ESMTP id B93F040698; Fri, 17 Jun 2022 09:02:40 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1655449361; x=1686985361; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=Pjl6z0zW24CzVp2kgEX6noqd0kSAO5o+yQnzTuplcNw=; b=Lksio9UXBP1A8z6bj48/6agXaLYbQ6c86kNVJbgZRVSwMQ0FkylzZ+Hy uorNmlWur8hu6VTjF5Ricy2sta8Mf7YrpOMtH4CdUIK5H6QI+B+RzzDxj PCgP090xqflrV62/QPXlEUp654Rv9Ju2puUdLO3uQT9s1PBbBrn38qYgU YrBpFJpW734hZjsxT5sFa7GwXtJWO6nxSy3XPJKgyiZF6OUjfSvct5g00 9neW1D/x0qLUNAoQj7zayWtFmVlI9dQkpkwaoWk4xXB+w+SP9NSp8GWAA QWHHFmbW/w1GNpog4oi1+LWVwYCOjUPpjqR7EZtEQlAoxffOQb5iXiO12 Q==; X-IronPort-AV: E=McAfee;i="6400,9594,10380"; a="304890224" X-IronPort-AV: E=Sophos;i="5.92,306,1650956400"; d="scan'208";a="304890224" Received: from fmsmga006.fm.intel.com ([10.253.24.20]) by fmsmga101.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 17 Jun 2022 00:02:39 -0700 X-IronPort-AV: E=Sophos;i="5.92,306,1650956400"; d="scan'208";a="831921994" Received: from unknown (HELO localhost.localdomain) ([10.239.252.55]) by fmsmga006-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 17 Jun 2022 00:02:37 -0700 From: Yuan Wang To: maxime.coquelin@redhat.com, chenbo.xia@intel.com, dev@dpdk.org Cc: jiayu.hu@intel.com, xingguang.he@intel.com, Yuan Wang , stable@dpdk.org, Wei Ling Subject: [PATCH v2] examples/vhost: fix retry logic on eth rx path Date: Fri, 17 Jun 2022 15:01:44 +0800 Message-Id: <20220617070144.710487-1-yuanx.wang@intel.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20220518162505.1691401-1-yuanx.wang@intel.com> References: <20220518162505.1691401-1-yuanx.wang@intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-BeenThere: stable@dpdk.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: patches for DPDK stable branches List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: stable-bounces@dpdk.org drain_eth_rx() uses rte_vhost_avail_entries() to calculate the available entries to determine if a retry is required. However, this function only works with split rings, and calculating packed rings will return the wrong value and cause unnecessary retries resulting in a significant performance penalty. This patch fix that by using the difference between tx/rx burst as the retry condition. Fixes: 4ecf22e356de ("vhost: export device id as the interface to applications") Cc: stable@dpdk.org Signed-off-by: Yuan Wang Tested-by: Wei Ling --- V2: Rebase to 22.07 rc1. --- examples/vhost/main.c | 27 ++++++++++----------------- 1 file changed, 10 insertions(+), 17 deletions(-) diff --git a/examples/vhost/main.c b/examples/vhost/main.c index e7fee5aa1b..e7a84333ed 100644 --- a/examples/vhost/main.c +++ b/examples/vhost/main.c @@ -634,7 +634,7 @@ us_vhost_usage(const char *prgname) { RTE_LOG(INFO, VHOST_CONFIG, "%s [EAL options] -- -p PORTMASK\n" " --vm2vm [0|1|2]\n" - " --rx_retry [0|1] --mergeable [0|1] --stats [0-N]\n" + " --rx-retry [0|1] --mergeable [0|1] --stats [0-N]\n" " --socket-file \n" " --nb-devices ND\n" " -p PORTMASK: Set mask for ports to be used by application\n" @@ -1383,27 +1383,20 @@ drain_eth_rx(struct vhost_dev *vdev) if (!rx_count) return; - /* - * When "enable_retry" is set, here we wait and retry when there - * is no enough free slots in the queue to hold @rx_count packets, - * to diminish packet loss. - */ - if (enable_retry && - unlikely(rx_count > rte_vhost_avail_entries(vdev->vid, - VIRTIO_RXQ))) { - uint32_t retry; + enqueue_count = vdev_queue_ops[vdev->vid].enqueue_pkt_burst(vdev, + VIRTIO_RXQ, pkts, rx_count); - for (retry = 0; retry < burst_rx_retry_num; retry++) { + /* Retry if necessary */ + if (enable_retry && unlikely(enqueue_count < rx_count)) { + uint32_t retry = 0; + + while (enqueue_count < rx_count && retry++ < burst_rx_retry_num) { rte_delay_us(burst_rx_delay_time); - if (rx_count <= rte_vhost_avail_entries(vdev->vid, - VIRTIO_RXQ)) - break; + enqueue_count += vdev_queue_ops[vdev->vid].enqueue_pkt_burst(vdev, + VIRTIO_RXQ, pkts, rx_count); } } - enqueue_count = vdev_queue_ops[vdev->vid].enqueue_pkt_burst(vdev, - VIRTIO_RXQ, pkts, rx_count); - if (enable_stats) { __atomic_add_fetch(&vdev->stats.rx_total_atomic, rx_count, __ATOMIC_SEQ_CST); -- 2.25.1