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 B5EDEA0032 for ; Fri, 15 Jul 2022 09:43:21 +0200 (CEST) Received: from [217.70.189.124] (localhost [127.0.0.1]) by mails.dpdk.org (Postfix) with ESMTP id 90DC040696; Fri, 15 Jul 2022 09:43:21 +0200 (CEST) Received: from mga18.intel.com (mga18.intel.com [134.134.136.126]) by mails.dpdk.org (Postfix) with ESMTP id E4B7B40042 for ; Fri, 15 Jul 2022 09:43:19 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1657871000; x=1689407000; h=from:to:cc:subject:date:message-id:mime-version: content-transfer-encoding; bh=Nf8yeUB41v0BxjiOtF/etW166/A9/AHQPFC6lTJuzEo=; b=HGRJ3wkEXm/G2MeBrkgtnXSaW2FS10mWewXoBhzKUDeKq9uAVGkxCvT5 jgI/LD1S3+qZ+CDdTQA4g0aopt0IiYPanRr9OxpiNIVafKGUNNlUEUCGZ iBKkPeThR0Fexsck/JyvOrC7ybUDFlqpQwJRMmab1m1ueByZTZKarEzTG 8ziMbux+8a+PWABbhWjyKCOoiTPeVNCIBlRUZel4X4c39hkPmwSJVCLY6 wDEcQUKEhpYp97Kz1FqRZYhCe9qZ3q5Rw4iYUY2mIxfuZfHT7KsISM3NS DmEazknznwfoiHNfv7UePtrL6T2WjDZXpusXo5jZYw+7gLQfDeIAg4bMq w==; X-IronPort-AV: E=McAfee;i="6400,9594,10408"; a="268751317" X-IronPort-AV: E=Sophos;i="5.92,273,1650956400"; d="scan'208";a="268751317" Received: from orsmga003.jf.intel.com ([10.7.209.27]) by orsmga106.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Jul 2022 00:43:18 -0700 X-IronPort-AV: E=Sophos;i="5.92,273,1650956400"; d="scan'208";a="546565024" Received: from unknown (HELO localhost.localdomain) ([10.239.252.55]) by orsmga003-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Jul 2022 00:43:10 -0700 From: Yuan Wang To: christian.ehrhardt@canonical.com, stable@dpdk.org Cc: maxime.coquelin@redhat.com, chenbo.xia@intel.com, jiayu.hu@intel.com, cheng1.jiang@intel.com, qiming.yang@intel.com, Yuan Wang Subject: [PATCH 19.11] examples/vhost: fix retry logic on Rx path Date: Fri, 15 Jul 2022 23:31:35 +0800 Message-Id: <20220715153135.566982-1-yuanx.wang@intel.com> X-Mailer: git-send-email 2.25.1 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 [ upstream commit 1907ce4baec392a750fbeba5e946920b2f00ae73 ] 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: be800696c26e ("examples/vhost: use burst enqueue and dequeue from lib") Signed-off-by: Yuan Wang Reviewed-by: Chenbo Xia --- examples/vhost/main.c | 40 ++++++++++++++++++++++------------------ 1 file changed, 22 insertions(+), 18 deletions(-) diff --git a/examples/vhost/main.c b/examples/vhost/main.c index 073668022..ca6e9a332 100644 --- a/examples/vhost/main.c +++ b/examples/vhost/main.c @@ -1051,24 +1051,6 @@ 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; - - for (retry = 0; retry < burst_rx_retry_num; retry++) { - rte_delay_us(burst_rx_delay_time); - if (rx_count <= rte_vhost_avail_entries(vdev->vid, - VIRTIO_RXQ)) - break; - } - } - if (builtin_net_driver) { enqueue_count = vs_enqueue_pkts(vdev, VIRTIO_RXQ, pkts, rx_count); @@ -1076,6 +1058,28 @@ drain_eth_rx(struct vhost_dev *vdev) enqueue_count = rte_vhost_enqueue_burst(vdev->vid, VIRTIO_RXQ, pkts, rx_count); } + + /* 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 (builtin_net_driver) { + enqueue_count += vs_enqueue_pkts(vdev, + VIRTIO_RXQ, &pkts[enqueue_count], + rx_count - enqueue_count); + } else { + enqueue_count += rte_vhost_enqueue_burst( + vdev->vid, + VIRTIO_RXQ, + &pkts[enqueue_count], + rx_count - enqueue_count); + } + } + } + if (enable_stats) { rte_atomic64_add(&vdev->stats.rx_total_atomic, rx_count); rte_atomic64_add(&vdev->stats.rx_atomic, enqueue_count); -- 2.25.1