On 08.08.2016 18:50, Mark Kavanagh wrote:
> 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.kavan...@intel.com>
> [diproiet...@vmware.com rebased]
> Signed-off-by: Daniele Di Proietto <diproiet...@vmware.com>
> ---
>
> 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
> - remove superflous variable in dpdk_mp_configure
> - fix minor coding style infraction
>
>
> INSTALL.DPDK-ADVANCED.md | 58 ++++++++++++++++-
> INSTALL.DPDK.md | 1 -
> NEWS | 1 +
> lib/netdev-dpdk.c | 162
> ++++++++++++++++++++++++++++++++++++++++-------
> 4 files changed, 194 insertions(+), 28 deletions(-)
>
> diff --git a/INSTALL.DPDK-ADVANCED.md b/INSTALL.DPDK-ADVANCED.md
> index 0ab43d4..5e758ce 100755
> --- a/INSTALL.DPDK-ADVANCED.md
> +++ b/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 b/INSTALL.DPDK.md
> index 253d022..a810ac8 100644
> --- a/INSTALL.DPDK.md
> +++ b/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..98ce3d0 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
> @@ -337,6 +338,7 @@ struct netdev_dpdk {
>
> struct dpdk_mp *dpdk_mp;
> int mtu;
> + int requested_mtu;
I think this should be placed near to other 'requested_*' variables somewhere
under the "The following properties cannot be changed when a device is
running...".
> int socket_id;
> int buf_size;
> struct netdev_stats stats;
> @@ -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 +531,33 @@ dpdk_mp_put(struct dpdk_mp *dmp) OVS_REQUIRES(dpdk_mutex)
> }
> }
>
> +/* Retrieve and configure a dpdk_mp that can accommodate dev's MTU.
> + * On success, decrement the refcount to dev's previous dpdk_mp (if
> applicable)
> + * and return 0.
> + * If insufficient memory is available to create dev's dpdk_mp, return
> ENOMEM.
> + */
> +static int
> +dpdk_mp_configure(struct netdev_dpdk *dev)
> + OVS_REQUIRES(dpdk_mutex)
> + OVS_REQUIRES(dev->mutex)
> +{
> + uint32_t buf_size = dpdk_buf_size(dev->mtu);
> + struct dpdk_mp *mp;
> +
> + mp = dpdk_mp_get(dev->socket_id, FRAME_LEN_TO_MTU(buf_size));
> + if (!mp) {
> + VLOG_ERR("Insufficient memory to create memory pool for netdev %s\n",
> + dev->up.name);
Socket id would be nice in this error report.
> + return ENOMEM;
> + } else {
> + dpdk_mp_put(dev->dpdk_mp);
> + dev->dpdk_mp = mp;
> + dev->max_packet_len = MTU_TO_FRAME_LEN(dev->mtu);
> + }
> +
> + return 0;
> +}
> +
> static void
> check_link_status(struct netdev_dpdk *dev)
> {
> @@ -571,7 +609,15 @@ 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 +628,10 @@ 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, rte_strerror(-diag));
> break;
> }
>
> @@ -736,7 +784,6 @@ 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 +804,13 @@ 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 = dpdk_mp_configure(dev);
> + if (err) {
> goto unlock;
> }
>
> @@ -991,6 +1036,7 @@ 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 +1412,7 @@ __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 +1434,41 @@ __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 +1702,26 @@ 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) {
Should we check for 'mtu < ETHER_MIN_MTU' here? I think it'll be nice
to check it here and pass only sane values to device. Otherwise
configuration will fail and device will be deleted.
> + VLOG_WARN("Unsupported MTU (%d)\n", mtu);
I prefer to mention name of the device in this message.
> + 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 +2886,8 @@ 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 +2895,18 @@ netdev_dpdk_reconfigure(struct netdev *netdev)
>
> rte_eth_dev_stop(dev->port_id);
>
> + if (dev->mtu != dev->requested_mtu) {
> + int prev_mtu = dev->mtu;
> +
> + dev->mtu = dev->requested_mtu;
> + err = dpdk_mp_configure(dev);
> + if (err) {
> + /* Revert to previous configuration; don't flag this as an error
> */
> + dev->mtu = prev_mtu;
> + err = 0;
> + }
How about to make this like in 'netdev_dpdk_vhost_user_reconfigure()' :
if (dpdk_mp_configure(dev)) {
/* Failed. Revert to previous configuration */
dev->mtu = prev_mtu;
}
?
> + }
> +
> netdev->n_txq = dev->requested_n_txq;
> netdev->n_rxq = dev->requested_n_rxq;
>
> @@ -2818,6 +2914,8 @@ 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 +2928,6 @@ 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);
> @@ -2845,14 +2942,19 @@ netdev_dpdk_vhost_user_reconfigure(struct netdev
> *netdev)
>
> netdev_dpdk_remap_txqs(dev);
>
> - if (dev->requested_socket_id != dev->socket_id) {
> + if (dev->requested_socket_id != dev->socket_id
> + || dev->requested_mtu != dev->mtu) {
> + int prev_mtu = dev->mtu;
> +
> 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;
> + dev->mtu = dev->requested_mtu;
> +
> + /* Change mempool to new NUMA Node and to new MTU.
> + * In the event of error, restore previous MTU. */
> + if (dpdk_mp_configure(dev)) {
'dev->socket_id' should be reverted too in this case.
Maybe it'll be better to add 2 arguments ('mtu' and 'socket_id') to
function 'dpdk_mp_configure()' and update real 'mtu' and 'socket_id'
only on success? Like this:
if (!dpdk_mp_configure(dev, dev->requested_mtu,
dev->requested_socket_id)) {
dev->socket_id = dev->requested_socket_id;
dev->mtu = dev->requested_mtu;
}
Another option is to rename 'dpdk_mp_configure' to
'netdev_dpdk_reconfigure_mempool' and use 'requested_{mtu, socket_id}'
inside and update real ones on success. Like this (not tested):
/* 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_reconfigure_mempool(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"
" on socket %d\n", dev->up.name, 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;
}
netdev_dpdk_vhost_user_reconfigure:
if (dev->requested_socket_id != dev->socket_id
|| dev->requested_mtu != dev->mtu) {
netdev_dpdk_reconfigure_mempool(dev);
}
Same in other places.
I prefer option with 'netdev_dpdk_reconfigure_mempool()'.
What do you think?
Best regards, Ilya Maximets.
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