[ovs-dev] [PATCH V7 7/7] netdev-dpdk: add support for jumbo frames

Daniele Di Proietto diproiettod at vmware.com
Sat Aug 13 02:50:53 UTC 2016


I pushed the reviewed patches to master and I'll post another series for the unit tests.


Thanks,

Daniele

On 09/08/2016 09:56, "Daniele Di Proietto" <diproiettod at ovn.org> wrote:

>Thanks for all the series and the reviews, I will push this when the dependencies (patch 2 and patch 6) are reviewed.
>
>
>
>Daniele
>
>
>2016-08-09 9:01 GMT-07:00 Mark Kavanagh 
><mark.b.kavanagh at intel.com>:
>
>Add support for Jumbo Frames to DPDK-enabled port types,
>using single-segment-mbufs.
>
>Using this approach, the amount of memory allocated to each mbuf
>to store frame data is increased to a value greater than 1518B
>(typical Ethernet maximum frame length). The increased space
>available in the mbuf means that an entire Jumbo Frame of a specific
>size can be carried in a single mbuf, as opposed to partitioning
>it across multiple mbuf segments.
>
>The amount of space allocated to each mbuf to hold frame data is
>defined dynamically by the user with ovs-vsctl, via the 'mtu_request'
>parameter.
>
>Signed-off-by: Mark Kavanagh <mark.b.kavanagh at intel.com>
>Signed-off-by: Ilya Maximets <i.maximets at samsung.com>
>[diproiettod at vmware.com rebased]
>Signed-off-by: Daniele Di Proietto <diproiettod at vmware.com>
>---
>
>v7:
>    - add 'Signed-off-by' for Ilya Maximets (i.maximets at samsung.com)
>
>v6:
>    - include device name in netdev_dpdk_set_mtu error log
>    - resolve minor coding standards infractions
>
>v5:
>    - rename dpdk_mp_configure to netdev_dpdk_mempool_configure
>    - consolidate socket_id and mtu changes within
>      netdev_dpdk_mempool_configure
>    - add lower bounds check for user-supplied MTU
>    - add socket_id and mtu fields to mempool configure error report
>    - minor cosmetic changes
>
>v4:
>    - restore error reporting in *_reconfigure functions (for
>      non-mtu-configuration based errors)
>    - remove 'goto' in the event of dpdk_mp_configure failure
>    - remove superfluous error variables
>
> v3:
>    - replace netdev_dpdk.last_mtu with local variable
>    - add comment for dpdk_mp_configure
>
> v2:
>     - rebase to HEAD of master
>     - fall back to previous 'good' MTU if reconfigure fails
>     - introduce new field 'last_mtu' in struct netdev_dpdk to facilitate
>       fall-back
>     - rename 'mtu_request' to 'requested_mtu' in struct netdev_dpdk
>     - remove rebasing artifact in 
>INSTALL.DPDK-Advanced.md <http://INSTALL.DPDK-Advanced.md>
>     - remove superflous variable in dpdk_mp_configure
>     - fix minor coding style infraction
>
>
> INSTALL.DPDK-ADVANCED.md <http://INSTALL.DPDK-ADVANCED.md> |  58 ++++++++++++++++++-
> INSTALL.DPDK.md <http://INSTALL.DPDK.md>          |   1 -
> NEWS                     |   1 +
> lib/netdev-dpdk.c        | 145 +++++++++++++++++++++++++++++++++++++++--------
> 4 files changed, 176 insertions(+), 29 deletions(-)
>
>diff --git a/INSTALL.DPDK-ADVANCED.md <http://INSTALL.DPDK-ADVANCED.md> b/INSTALL.DPDK-ADVANCED.md <http://INSTALL.DPDK-ADVANCED.md>
>index 0ab43d4..5e758ce 100755
>--- a/INSTALL.DPDK-ADVANCED.md <http://INSTALL.DPDK-ADVANCED.md>
>+++ b/INSTALL.DPDK-ADVANCED.md <http://INSTALL.DPDK-ADVANCED.md>
>@@ -1,5 +1,5 @@
> OVS DPDK ADVANCED INSTALL GUIDE
>-=================================
>+===============================
>
> ## Contents
>
>@@ -12,7 +12,8 @@ OVS DPDK ADVANCED INSTALL GUIDE
> 7. [QOS](#qos)
> 8. [Rate Limiting](#rl)
> 9. [Flow Control](#fc)
>-10. [Vsperf](#vsperf)
>+10. [Jumbo Frames](#jumbo)
>+11. [Vsperf](#vsperf)
>
> ## <a name="overview"></a> 1. Overview
>
>@@ -862,7 +863,58 @@ respective parameter. To disable the flow control at tx side,
>
> `ovs-vsctl set Interface dpdk0 options:tx-flow-ctrl=false`
>
>-## <a name="vsperf"></a> 10. Vsperf
>+## <a name="jumbo"></a> 10. Jumbo Frames
>+
>+By default, DPDK ports are configured with standard Ethernet MTU (1500B). To
>+enable Jumbo Frames support for a DPDK port, change the Interface's `mtu_request`
>+attribute to a sufficiently large value.
>+
>+e.g. Add a DPDK Phy port with MTU of 9000:
>+
>+`ovs-vsctl add-port br0 dpdk0 -- set Interface dpdk0 type=dpdk -- set Interface dpdk0 mtu_request=9000`
>+
>+e.g. Change the MTU of an existing port to 6200:
>+
>+`ovs-vsctl set Interface dpdk0 mtu_request=6200`
>+
>+When Jumbo Frames are enabled, the size of a DPDK port's mbuf segments are
>+increased, such that a full Jumbo Frame of a specific size may be accommodated
>+within a single mbuf segment.
>+
>+Jumbo frame support has been validated against 9728B frames (largest frame size
>+supported by Fortville NIC), using the DPDK `i40e` driver, but larger frames
>+(particularly in use cases involving East-West traffic only), and other DPDK NIC
>+drivers may be supported.
>+
>+### 9.1 vHost Ports and Jumbo Frames
>+
>+Some additional configuration is needed to take advantage of jumbo frames with
>+vhost ports:
>+
>+    1. `mergeable buffers` must be enabled for vHost ports, as demonstrated in
>+        the QEMU command line snippet below:
>+
>+        ```
>+        '-netdev type=vhost-user,id=mynet1,chardev=char0,vhostforce \'
>+        '-device virtio-net-pci,mac=00:00:00:00:00:01,netdev=mynet1,mrg_rxbuf=on'
>+        ```
>+
>+    2. Where virtio devices are bound to the Linux kernel driver in a guest
>+       environment (i.e. interfaces are not bound to an in-guest DPDK driver),
>+       the MTU of those logical network interfaces must also be increased to a
>+       sufficiently large value. This avoids segmentation of Jumbo Frames
>+       received in the guest. Note that 'MTU' refers to the length of the IP
>+       packet only, and not that of the entire frame.
>+
>+       To calculate the exact MTU of a standard IPv4 frame, subtract the L2
>+       header and CRC lengths (i.e. 18B) from the max supported frame size.
>+       So, to set the MTU for a 9018B Jumbo Frame:
>+
>+       ```
>+       ifconfig eth1 mtu 9000
>+       ```
>+
>+## <a name="vsperf"></a> 11. Vsperf
>
> Vsperf project goal is to develop vSwitch test framework that can be used to
> validate the suitability of different vSwitch implementations in a Telco deployment
>diff --git a/INSTALL.DPDK.md <http://INSTALL.DPDK.md> b/INSTALL.DPDK.md <http://INSTALL.DPDK.md>
>index 253d022..a810ac8 100644
>--- a/INSTALL.DPDK.md <http://INSTALL.DPDK.md>
>+++ b/INSTALL.DPDK.md <http://INSTALL.DPDK.md>
>@@ -590,7 +590,6 @@ can be found in [Vhost Walkthrough].
>
> ## <a name="ovslimits"></a> 6. Limitations
>
>-  - Supports MTU size 1500, MTU setting for DPDK netdevs will be in future OVS release.
>   - Currently DPDK ports does not use HW offload functionality.
>   - Network Interface Firmware requirements:
>     Each release of DPDK is validated against a specific firmware version for
>diff --git a/NEWS b/NEWS
>index ce10982..53c816b 100644
>--- a/NEWS
>+++ b/NEWS
>@@ -69,6 +69,7 @@ Post-v2.5.0
>      * Basic connection tracking for the userspace datapath (no ALG,
>        fragmentation or NAT support yet)
>      * Support for DPDK 16.07
>+     * Jumbo frame support
>    - Increase number of registers to 16.
>    - ovs-benchmark: This utility has been removed due to lack of use and
>      bitrot.
>diff --git a/lib/netdev-dpdk.c b/lib/netdev-dpdk.c
>index 60db568..bd29a06 100644
>--- a/lib/netdev-dpdk.c
>+++ b/lib/netdev-dpdk.c
>@@ -81,6 +81,7 @@ static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(5, 20);
>                                     + sizeof(struct dp_packet)    \
>                                     + RTE_PKTMBUF_HEADROOM)
> #define NETDEV_DPDK_MBUF_ALIGN      1024
>+#define NETDEV_DPDK_MAX_PKT_LEN     9728
>
> /* Max and min number of packets in the mempool.  OVS tries to allocate a
>  * mempool with MAX_NB_MBUF: if this fails (because the system doesn't have
>@@ -368,6 +369,7 @@ struct netdev_dpdk {
>     /* The following properties cannot be changed when a device is running,
>      * so we remember the request and update them next time
>      * netdev_dpdk*_reconfigure() is called */
>+    int requested_mtu;
>     int requested_n_txq;
>     int requested_n_rxq;
>
>@@ -477,10 +479,19 @@ dpdk_mp_get(int socket_id, int mtu) OVS_REQUIRES(dpdk_mutex)
>     dmp->mtu = mtu;
>     dmp->refcount = 1;
>     mbp_priv.mbuf_data_room_size = MBUF_SIZE(mtu) - sizeof(struct dp_packet);
>-    mbp_priv.mbuf_priv_size = sizeof (struct dp_packet) -
>-                              sizeof (struct rte_mbuf);
>+    mbp_priv.mbuf_priv_size = sizeof (struct dp_packet)
>+                              - sizeof (struct rte_mbuf);
>+    /* XXX: this is a really rough method of provisioning memory.
>+     * It's impossible to determine what the exact memory requirements are when
>+     * the number of ports and rxqs that utilize a particular mempool can change
>+     * dynamically at runtime. For the moment, use this rough heurisitic.
>+     */
>+    if (mtu >= ETHER_MTU) {
>+        mp_size = MAX_NB_MBUF;
>+    } else {
>+        mp_size = MIN_NB_MBUF;
>+    }
>
>-    mp_size = MAX_NB_MBUF;
>     do {
>         if (snprintf(mp_name, RTE_MEMPOOL_NAMESIZE, "ovs_mp_%d_%d_%u",
>                      dmp->mtu, dmp->socket_id, mp_size) < 0) {
>@@ -520,6 +531,35 @@ dpdk_mp_put(struct dpdk_mp *dmp) OVS_REQUIRES(dpdk_mutex)
>     }
> }
>
>+/* Tries to allocate new mempool on requested_socket_id with
>+ * mbuf size corresponding to requested_mtu.
>+ * On success new configuration will be applied.
>+ * On error, device will be left unchanged. */
>+static int
>+netdev_dpdk_mempool_configure(struct netdev_dpdk *dev)
>+    OVS_REQUIRES(dpdk_mutex)
>+    OVS_REQUIRES(dev->mutex)
>+{
>+    uint32_t buf_size = dpdk_buf_size(dev->requested_mtu);
>+    struct dpdk_mp *mp;
>+
>+    mp = dpdk_mp_get(dev->requested_socket_id, FRAME_LEN_TO_MTU(buf_size));
>+    if (!mp) {
>+        VLOG_ERR("Insufficient memory to create memory pool for netdev "
>+                 "%s, with MTU %d on socket %d\n",
>+                 dev->up.name <http://up.name>, dev->requested_mtu, dev->requested_socket_id);
>+        return ENOMEM;
>+    } else {
>+        dpdk_mp_put(dev->dpdk_mp);
>+        dev->dpdk_mp = mp;
>+        dev->mtu = dev->requested_mtu;
>+        dev->socket_id = dev->requested_socket_id;
>+        dev->max_packet_len = MTU_TO_FRAME_LEN(dev->mtu);
>+    }
>+
>+    return 0;
>+}
>+
> static void
> check_link_status(struct netdev_dpdk *dev)
> {
>@@ -571,7 +611,15 @@ dpdk_eth_dev_queue_setup(struct netdev_dpdk *dev, int n_rxq, int n_txq)
> {
>     int diag = 0;
>     int i;
>+    struct rte_eth_conf conf = port_conf;
>
>+    if (dev->mtu > ETHER_MTU) {
>+        conf.rxmode.jumbo_frame = 1;
>+        conf.rxmode.max_rx_pkt_len = dev->max_packet_len;
>+    } else {
>+        conf.rxmode.jumbo_frame = 0;
>+        conf.rxmode.max_rx_pkt_len = 0;
>+    }
>     /* A device may report more queues than it makes available (this has
>      * been observed for Intel xl710, which reserves some of them for
>      * SRIOV):  rte_eth_*_queue_setup will fail if a queue is not
>@@ -582,8 +630,10 @@ dpdk_eth_dev_queue_setup(struct netdev_dpdk *dev, int n_rxq, int n_txq)
>             VLOG_INFO("Retrying setup with (rxq:%d txq:%d)", n_rxq, n_txq);
>         }
>
>-        diag = rte_eth_dev_configure(dev->port_id, n_rxq, n_txq, &port_conf);
>+        diag = rte_eth_dev_configure(dev->port_id, n_rxq, n_txq, &conf);
>         if (diag) {
>+            VLOG_WARN("Interface %s eth_dev setup error %s\n",
>+                      dev->up.name <http://up.name>, rte_strerror(-diag));
>             break;
>         }
>
>@@ -736,7 +786,6 @@ netdev_dpdk_init(struct netdev *netdev, unsigned int port_no,
>     struct netdev_dpdk *dev = netdev_dpdk_cast(netdev);
>     int sid;
>     int err = 0;
>-    uint32_t buf_size;
>
>     ovs_mutex_init(&dev->mutex);
>     ovs_mutex_lock(&dev->mutex);
>@@ -757,15 +806,13 @@ netdev_dpdk_init(struct netdev *netdev, unsigned int port_no,
>     dev->port_id = port_no;
>     dev->type = type;
>     dev->flags = 0;
>-    dev->mtu = ETHER_MTU;
>+    dev->requested_mtu = dev->mtu = ETHER_MTU;
>     dev->max_packet_len = MTU_TO_FRAME_LEN(dev->mtu);
>     ovsrcu_index_init(&dev->vid, -1);
>     dev->vhost_reconfigured = false;
>
>-    buf_size = dpdk_buf_size(dev->mtu);
>-    dev->dpdk_mp = dpdk_mp_get(dev->socket_id, FRAME_LEN_TO_MTU(buf_size));
>-    if (!dev->dpdk_mp) {
>-        err = ENOMEM;
>+    err = netdev_dpdk_mempool_configure(dev);
>+    if (err) {
>         goto unlock;
>     }
>
>@@ -991,6 +1038,7 @@ netdev_dpdk_get_config(const struct netdev *netdev, struct smap *args)
>     smap_add_format(args, "configured_rx_queues", "%d", netdev->n_rxq);
>     smap_add_format(args, "requested_tx_queues", "%d", dev->requested_n_txq);
>     smap_add_format(args, "configured_tx_queues", "%d", netdev->n_txq);
>+    smap_add_format(args, "mtu", "%d", dev->mtu);
>     ovs_mutex_unlock(&dev->mutex);
>
>     return 0;
>@@ -1366,6 +1414,7 @@ __netdev_dpdk_vhost_send(struct netdev *netdev, int qid,
>     struct rte_mbuf **cur_pkts = (struct rte_mbuf **) pkts;
>     unsigned int total_pkts = cnt;
>     unsigned int qos_pkts = cnt;
>+    unsigned int mtu_dropped = 0;
>     int retries = 0;
>
>     qid = dev->tx_q[qid % netdev->n_txq].map;
>@@ -1387,25 +1436,41 @@ __netdev_dpdk_vhost_send(struct netdev *netdev, int qid,
>     do {
>         int vhost_qid = qid * VIRTIO_QNUM + VIRTIO_RXQ;
>         unsigned int tx_pkts;
>+        unsigned int try_tx_pkts = cnt;
>
>+        for (unsigned int i = 0; i < cnt; i++) {
>+            if (cur_pkts[i]->pkt_len > dev->max_packet_len) {
>+                try_tx_pkts = i;
>+                break;
>+            }
>+        }
>+        if (!try_tx_pkts) {
>+            cur_pkts++;
>+            mtu_dropped++;
>+            cnt--;
>+            continue;
>+        }
>         tx_pkts = rte_vhost_enqueue_burst(netdev_dpdk_get_vid(dev),
>-                                          vhost_qid, cur_pkts, cnt);
>+                                          vhost_qid, cur_pkts, try_tx_pkts);
>         if (OVS_LIKELY(tx_pkts)) {
>             /* Packets have been sent.*/
>             cnt -= tx_pkts;
>             /* Prepare for possible retry.*/
>             cur_pkts = &cur_pkts[tx_pkts];
>+            if (tx_pkts != try_tx_pkts) {
>+                retries++;
>+            }
>         } else {
>             /* No packets sent - do not retry.*/
>             break;
>         }
>-    } while (cnt && (retries++ < VHOST_ENQ_RETRY_NUM));
>+    } while (cnt && (retries <= VHOST_ENQ_RETRY_NUM));
>
>     rte_spinlock_unlock(&dev->tx_q[qid].tx_lock);
>
>     rte_spinlock_lock(&dev->stats_lock);
>-    cnt += qos_pkts;
>-    netdev_dpdk_vhost_update_tx_counters(&dev->stats, pkts, total_pkts, cnt);
>+    netdev_dpdk_vhost_update_tx_counters(&dev->stats, pkts, total_pkts,
>+                                         cnt + mtu_dropped + qos_pkts);
>     rte_spinlock_unlock(&dev->stats_lock);
>
> out:
>@@ -1639,6 +1704,27 @@ netdev_dpdk_get_mtu(const struct netdev *netdev, int *mtup)
> }
>
> static int
>+netdev_dpdk_set_mtu(struct netdev *netdev, int mtu)
>+{
>+    struct netdev_dpdk *dev = netdev_dpdk_cast(netdev);
>+
>+    if (MTU_TO_FRAME_LEN(mtu) > NETDEV_DPDK_MAX_PKT_LEN
>+        || mtu < ETHER_MIN_MTU) {
>+        VLOG_WARN("%s: unsupported MTU %d\n", dev->up.name <http://up.name>, mtu);
>+        return EINVAL;
>+    }
>+
>+    ovs_mutex_lock(&dev->mutex);
>+    if (dev->requested_mtu != mtu) {
>+        dev->requested_mtu = mtu;
>+        netdev_request_reconfigure(netdev);
>+    }
>+    ovs_mutex_unlock(&dev->mutex);
>+
>+    return 0;
>+}
>+
>+static int
> netdev_dpdk_get_carrier(const struct netdev *netdev, bool *carrier);
>
> static int
>@@ -2803,7 +2889,8 @@ netdev_dpdk_reconfigure(struct netdev *netdev)
>     ovs_mutex_lock(&dev->mutex);
>
>     if (netdev->n_txq == dev->requested_n_txq
>-        && netdev->n_rxq == dev->requested_n_rxq) {
>+        && netdev->n_rxq == dev->requested_n_rxq
>+        && dev->mtu == dev->requested_mtu) {
>         /* Reconfiguration is unnecessary */
>
>         goto out;
>@@ -2811,6 +2898,10 @@ netdev_dpdk_reconfigure(struct netdev *netdev)
>
>     rte_eth_dev_stop(dev->port_id);
>
>+    if (dev->mtu != dev->requested_mtu) {
>+        netdev_dpdk_mempool_configure(dev);
>+    }
>+
>     netdev->n_txq = dev->requested_n_txq;
>     netdev->n_rxq = dev->requested_n_rxq;
>
>@@ -2818,6 +2909,8 @@ netdev_dpdk_reconfigure(struct netdev *netdev)
>     err = dpdk_eth_dev_init(dev);
>     netdev_dpdk_alloc_txq(dev, netdev->n_txq);
>
>+    netdev_change_seq_changed(netdev);
>+
> out:
>
>     ovs_mutex_unlock(&dev->mutex);
>@@ -2830,7 +2923,6 @@ static int
> netdev_dpdk_vhost_user_reconfigure(struct netdev *netdev)
> {
>     struct netdev_dpdk *dev = netdev_dpdk_cast(netdev);
>-    int err = 0;
>
>     ovs_mutex_lock(&dpdk_mutex);
>     ovs_mutex_lock(&dev->mutex);
>@@ -2845,13 +2937,10 @@ netdev_dpdk_vhost_user_reconfigure(struct netdev *netdev)
>
>     netdev_dpdk_remap_txqs(dev);
>
>-    if (dev->requested_socket_id != dev->socket_id) {
>-        dev->socket_id = dev->requested_socket_id;
>-        /* Change mempool to new NUMA Node */
>-        dpdk_mp_put(dev->dpdk_mp);
>-        dev->dpdk_mp = dpdk_mp_get(dev->socket_id, dev->mtu);
>-        if (!dev->dpdk_mp) {
>-            err = ENOMEM;
>+    if (dev->requested_socket_id != dev->socket_id
>+        || dev->requested_mtu != dev->mtu) {
>+        if (!netdev_dpdk_mempool_configure(dev)) {
>+            netdev_change_seq_changed(netdev);
>         }
>     }
>
>@@ -2862,7 +2951,7 @@ netdev_dpdk_vhost_user_reconfigure(struct netdev *netdev)
>     ovs_mutex_unlock(&dev->mutex);
>     ovs_mutex_unlock(&dpdk_mutex);
>
>-    return err;
>+    return 0;
> }
>
> static int
>@@ -2876,6 +2965,12 @@ netdev_dpdk_vhost_cuse_reconfigure(struct netdev *netdev)
>     netdev->n_txq = dev->requested_n_txq;
>     netdev->n_rxq = 1;
>
>+    if (dev->requested_mtu != dev->mtu) {
>+        if (!netdev_dpdk_mempool_configure(dev)) {
>+            netdev_change_seq_changed(netdev);
>+        }
>+    }
>+
>     ovs_mutex_unlock(&dev->mutex);
>     ovs_mutex_unlock(&dpdk_mutex);
>
>@@ -2913,7 +3008,7 @@ netdev_dpdk_vhost_cuse_reconfigure(struct netdev *netdev)
>     netdev_dpdk_set_etheraddr,                                \
>     netdev_dpdk_get_etheraddr,                                \
>     netdev_dpdk_get_mtu,                                      \
>-    NULL,                       /* set_mtu */                 \
>+    netdev_dpdk_set_mtu,                                      \
>     netdev_dpdk_get_ifindex,                                  \
>     GET_CARRIER,                                              \
>     netdev_dpdk_get_carrier_resets,                           \
>--
>1.9.3
>
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