From patchwork Mon Dec 28 16:22:33 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Willem de Bruijn X-Patchwork-Id: 352917 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A0FEEC4332D for ; Mon, 28 Dec 2020 16:23:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 87F8A20867 for ; Mon, 28 Dec 2020 16:23:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2633318AbgL1QX2 (ORCPT ); Mon, 28 Dec 2020 11:23:28 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52042 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2441017AbgL1QXV (ORCPT ); Mon, 28 Dec 2020 11:23:21 -0500 Received: from mail-qk1-x734.google.com (mail-qk1-x734.google.com [IPv6:2607:f8b0:4864:20::734]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D2906C061798 for ; Mon, 28 Dec 2020 08:22:40 -0800 (PST) Received: by mail-qk1-x734.google.com with SMTP id h4so9222957qkk.4 for ; Mon, 28 Dec 2020 08:22:40 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=uPsSfUcgHKgBzIXc3fN7YUqB8K9nJMunTZsde3ErHn4=; b=Xf0U70enwHW9IE8UGZVUnVIVEA0/1QMa+Unw2Hvs5voiItNagr8wOqb3rTN6qtLyyM 2ADTZISRtDDTotVM/uwXgEPL23oP1/cusS33uE6wGl8QeZwRQ+3+JYlWuZb/zWAesI3m 7JfTQsiGGjhJIAqky4jzDVjlH1LoiEPLMvBLOGDiA2GWIV73XXw1pMnkufdYO6/wdk8Y qTPP9EorAaSNWuEhFKTcqkzidcQjWghsBc+WxyVA9O7ZUwvCJ1EIxyMSnJT5AJB+lARJ 4fq4yhWzH4y55tOWWNCjYFb6e0WCSqMHlb4GrIIbfgcqGBKfuYkK1kjW8BmsElawttUB k7aQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=uPsSfUcgHKgBzIXc3fN7YUqB8K9nJMunTZsde3ErHn4=; b=hq97Z0YfWlH0rcxw1l2sG+JYuLW3LFq813j/9+NRa56ltg4QyilFbdtHI4jIdDzRIi ufDDcXMoo33mZeEoc9Ch1026z8xOuTQsXSTNFs9i4FEplKNvQowyZjrgRjGGCpiYYlY3 acNydisOl4D++O+RKdQ9jOrtBWeHK3cxJVK0U3s9sy1PJqmBpuryF6khBz6VavLcHmiK hj1jY121sFy46T7JWPxtizz6iUa3ac5FFiGrGqZjAqjr8t+hCdMXlg/Qaz8eMWM4r25v jFfyFkgxPnUMcshGvN9N7xkOAmNVswuYlXS8j2GO26f4TV6TmjtrwJGNcRYRMf/GceKQ YXXA== X-Gm-Message-State: AOAM531Dbj20R3fPVBCxSzHxs+OXSfzdnqAt/vi0h+dw/dap3Z3av391 mnEohQlhMnp7gnXgAKZmXTQ= X-Google-Smtp-Source: ABdhPJxplx0oHVIyDzXmxBVOqgqLZvlzZAjkoslvEhIVjuqNIZ1evoBz2Od6TWBfCKaXMkzVsnsl/g== X-Received: by 2002:a37:8204:: with SMTP id e4mr40690939qkd.351.1609172560145; Mon, 28 Dec 2020 08:22:40 -0800 (PST) Received: from willemb.nyc.corp.google.com ([2620:0:1003:312:f693:9fff:fef4:3e8a]) by smtp.gmail.com with ESMTPSA id u65sm24005556qkb.58.2020.12.28.08.22.39 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 28 Dec 2020 08:22:39 -0800 (PST) From: Willem de Bruijn To: virtualization@lists.linux-foundation.org Cc: netdev@vger.kernel.org, mst@redhat.com, jasowang@redhat.com, Willem de Bruijn Subject: [PATCH rfc 3/3] virtio-net: support transmit timestamp Date: Mon, 28 Dec 2020 11:22:33 -0500 Message-Id: <20201228162233.2032571-4-willemdebruijn.kernel@gmail.com> X-Mailer: git-send-email 2.29.2.729.g45daf8777d-goog In-Reply-To: <20201228162233.2032571-1-willemdebruijn.kernel@gmail.com> References: <20201228162233.2032571-1-willemdebruijn.kernel@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Willem de Bruijn Add optional delivery time (SO_TXTIME) offload for virtio-net. The Linux TCP/IP stack tries to avoid bursty transmission and network congestion through pacing: computing an skb delivery time based on congestion information. Userspace protocol implementations can achieve the same with SO_TXTIME. This may also reduce scheduling jitter and improve RTT estimation. Pacing can be implemented in ETF or FQ qdiscs or offloaded to NIC hardware. Allow guests to offload for the same reasons. The timestamp straddles (virtual) hardware domains. Like PTP, use international atomic time (CLOCK_TAI) as global clock base. It is guest responsibility to sync with host, e.g., through kvm-clock. Signed-off-by: Willem de Bruijn Reported-by: kernel test robot --- drivers/net/virtio_net.c | 24 +++++++++++++++++------- include/uapi/linux/virtio_net.h | 1 + 2 files changed, 18 insertions(+), 7 deletions(-) diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index 57744bb6a141..d40be688aed0 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -207,6 +207,9 @@ struct virtnet_info { /* Host will pass CLOCK_TAI receive time to the guest */ bool has_rx_tstamp; + /* Guest will pass CLOCK_TAI delivery time to the host */ + bool has_tx_tstamp; + /* Has control virtqueue */ bool has_cvq; @@ -1550,7 +1553,7 @@ static int xmit_skb(struct send_queue *sq, struct sk_buff *skb) struct virtio_net_hdr_mrg_rxbuf *hdr; const unsigned char *dest = ((struct ethhdr *)skb->data)->h_dest; struct virtnet_info *vi = sq->vq->vdev->priv; - struct virtio_net_hdr_v1_hash *ht; + struct virtio_net_hdr_v12 *h12; int num_sg; unsigned hdr_len = vi->hdr_len; bool can_push; @@ -1575,13 +1578,15 @@ static int xmit_skb(struct send_queue *sq, struct sk_buff *skb) if (vi->mergeable_rx_bufs) hdr->num_buffers = 0; - ht = (void *)hdr; + h12 = (void *)hdr; if (vi->has_tx_hash) { - ht->hash_value = cpu_to_virtio32(vi->vdev, skb->hash); - ht->hash_report = skb->l4_hash ? VIRTIO_NET_HASH_REPORT_L4 : - VIRTIO_NET_HASH_REPORT_OTHER; - ht->hash_state = VIRTIO_NET_HASH_STATE_DEFAULT; + h12->hash.value = cpu_to_virtio32(vi->vdev, skb->hash); + h12->hash.report = skb->l4_hash ? VIRTIO_NET_HASH_REPORT_L4 : + VIRTIO_NET_HASH_REPORT_OTHER; + h12->hash.flow_state = VIRTIO_NET_HASH_STATE_DEFAULT; } + if (vi->has_tx_tstamp) + h12->tstamp = cpu_to_virtio64(vi->vdev, skb->tstamp); sg_init_table(sq->sg, skb_shinfo(skb)->nr_frags + (can_push ? 1 : 2)); if (can_push) { @@ -3089,6 +3094,11 @@ static int virtnet_probe(struct virtio_device *vdev) vi->hdr_len = sizeof(struct virtio_net_hdr_v12); } + if (virtio_has_feature(vdev, VIRTIO_NET_F_TX_TSTAMP)) { + vi->has_tx_tstamp = true; + vi->hdr_len = sizeof(struct virtio_net_hdr_v12); + } + if (virtio_has_feature(vdev, VIRTIO_F_ANY_LAYOUT) || virtio_has_feature(vdev, VIRTIO_F_VERSION_1)) vi->any_header_sg = true; @@ -3279,7 +3289,7 @@ static struct virtio_device_id id_table[] = { VIRTIO_NET_F_CTRL_MAC_ADDR, \ VIRTIO_NET_F_MTU, VIRTIO_NET_F_CTRL_GUEST_OFFLOADS, \ VIRTIO_NET_F_SPEED_DUPLEX, VIRTIO_NET_F_STANDBY, \ - VIRTIO_NET_F_TX_HASH, VIRTIO_NET_F_RX_TSTAMP + VIRTIO_NET_F_TX_HASH, VIRTIO_NET_F_RX_TSTAMP, VIRTIO_NET_F_TX_TSTAMP static unsigned int features[] = { VIRTNET_FEATURES, diff --git a/include/uapi/linux/virtio_net.h b/include/uapi/linux/virtio_net.h index 0ffe2eeebd4a..da017a47791d 100644 --- a/include/uapi/linux/virtio_net.h +++ b/include/uapi/linux/virtio_net.h @@ -57,6 +57,7 @@ * Steering */ #define VIRTIO_NET_F_CTRL_MAC_ADDR 23 /* Set MAC address */ +#define VIRTIO_NET_F_TX_TSTAMP 54 /* Guest sets TAI delivery time */ #define VIRTIO_NET_F_RX_TSTAMP 55 /* Host sends TAI receive time */ #define VIRTIO_NET_F_TX_HASH 56 /* Guest sends hash report */ #define VIRTIO_NET_F_HASH_REPORT 57 /* Supports hash report */