[ovs-dev] [PATCH V5 2/2] netdev-dpdk: add jumbo frame support
Mark Kavanagh
mark.b.kavanagh at intel.com
Fri Feb 19 11:25:12 UTC 2016
Add support for Jumbo Frames to DPDK-enabled port types,
using single-segment-mbufs.
Using this approach, the amount of memory allocated for 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 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 when adding a DPDK port to a bridge.
If an MTU value is not supplied, or the user-supplied value is invalid,
the MTU for the port defaults to standard Ethernet MTU (i.e. 1500B).
Signed-off-by: Mark Kavanagh <mark.b.kavanagh at intel.com>
---
INSTALL.DPDK.md | 60 ++++++++++++-
NEWS | 3 +-
lib/netdev-dpdk.c | 248 +++++++++++++++++++++++++++++++++++++-----------------
3 files changed, 233 insertions(+), 78 deletions(-)
diff --git a/INSTALL.DPDK.md b/INSTALL.DPDK.md
index d892788..4ca98cb 100644
--- a/INSTALL.DPDK.md
+++ b/INSTALL.DPDK.md
@@ -878,10 +878,63 @@ by adding the following string:
to <interface> sections of all network devices used by DPDK. Parameter 'N'
determines how many queues can be used by the guest.
+Jumbo Frames
+------------
+
+Support for Jumbo Frames may be enabled at run-time for DPDK-type ports.
+
+To avail of Jumbo Frame support, add the 'mtu_request' option to the ovs-vsctl
+'add-port' command-line, along with the required MTU for the port.
+e.g.
+
+ ```
+ ovs-vsctl add-port br0 dpdk0 -- set Interface dpdk0 type=dpdk options:mtu_request=9000
+ ```
+
+When Jumbo Frames are enabled, the size of a DPDK port's mbuf segments are
+increased, such that a full Jumbo Frame may be accommodated inside a single
+mbuf segment. Once set, the MTU for a DPDK port is immutable.
+
+Note that from an OVSDB perspective, the `mtu_request` option for a specific
+port may be disregarded once initially set, as subsequent modifications to this
+field are disregarded by the DPDK port. As with non-DPDK ports, the MTU of DPDK
+ports is reported by the `Interface` table's 'mtu' field.
+
+Jumbo frame support has been validated against 13312B frames, using the
+DPDK `igb_uio` driver, but larger frames and other DPDK NIC drivers may
+theoretically be supported. Supported port types excludes vHost-Cuse ports, as
+that feature is pending deprecation.
+
+vHost Ports and Jumbo Frames
+----------------------------
+Jumbo frame support is available for DPDK vHost-User ports only. Some additional
+configuration is needed to take advantage of this feature:
+
+ 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. This
+ avoids segmentation of Jumbo Frames in the guest. Note that 'MTU' refers
+ to the length of the IP packet only, and not that of the entire frame.
+
+ e.g. 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 13312B Jumbo Frame:
+
+ ```
+ ifconfig eth1 mtu 13294
+ ```
+
Restrictions:
-------------
- - Work with 1500 MTU, needs few changes in DPDK lib to fix this issue.
- Currently DPDK port does not make use any offload functionality.
- DPDK-vHost support works with 1G huge pages.
@@ -922,6 +975,11 @@ Restrictions:
the next release of DPDK (which includes the above patch) is available and
integrated into OVS.
+ Jumbo Frames:
+ - `virtio-pmd`: DPDK apps in the guest do not exit gracefully. This is a DPDK
+ issue that is currently being investigated.
+ - vHost-Cuse: Jumbo Frame support is not available for vHost Cuse ports.
+
Bug Reporting:
--------------
diff --git a/NEWS b/NEWS
index 3e33871..43127f9 100644
--- a/NEWS
+++ b/NEWS
@@ -10,10 +10,11 @@ Post-v2.5.0
- DPDK:
* New option "n_rxq" for PMD interfaces.
Old 'other_config:n-dpdk-rxqs' is no longer supported.
+ * Support Jumbo Frames
+
- ovs-benchmark: This utility has been removed due to lack of use and
bitrot.
-
v2.5.0 - xx xxx xxxx
---------------------
- Dropped support for Python older than version 2.7. As a consequence,
diff --git a/lib/netdev-dpdk.c b/lib/netdev-dpdk.c
index 2a06bb5..ac89ee6 100644
--- a/lib/netdev-dpdk.c
+++ b/lib/netdev-dpdk.c
@@ -77,6 +77,8 @@ 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_FRAME_LEN 13312
+#define MTU_NOT_SET 0
/* 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
@@ -422,6 +424,7 @@ 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;
/* A device may report more queues than it makes available (this has
* been observed for Intel xl710, which reserves some of them for
@@ -433,7 +436,15 @@ 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);
+ 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;
+ }
+
+ diag = rte_eth_dev_configure(dev->port_id, n_rxq, n_txq, &conf);
if (diag) {
break;
}
@@ -574,8 +585,6 @@ netdev_dpdk_init(struct netdev *netdev_, unsigned int port_no,
{
struct netdev_dpdk *netdev = netdev_dpdk_cast(netdev_);
int sid;
- int err = 0;
- uint32_t buf_size;
ovs_mutex_init(&netdev->mutex);
ovs_mutex_lock(&netdev->mutex);
@@ -595,15 +604,7 @@ netdev_dpdk_init(struct netdev *netdev_, unsigned int port_no,
netdev->port_id = port_no;
netdev->type = type;
netdev->flags = 0;
- netdev->mtu = ETHER_MTU;
- netdev->max_packet_len = MTU_TO_FRAME_LEN(netdev->mtu);
-
- buf_size = dpdk_buf_size(netdev->mtu);
- netdev->dpdk_mp = dpdk_mp_get(netdev->socket_id, FRAME_LEN_TO_MTU(buf_size));
- if (!netdev->dpdk_mp) {
- err = ENOMEM;
- goto unlock;
- }
+ netdev->mtu = MTU_NOT_SET;
netdev_->n_txq = NR_QUEUE;
netdev_->n_rxq = NR_QUEUE;
@@ -612,20 +613,12 @@ netdev_dpdk_init(struct netdev *netdev_, unsigned int port_no,
if (type == DPDK_DEV_ETH) {
netdev_dpdk_alloc_txq(netdev, NR_QUEUE);
- err = dpdk_eth_dev_init(netdev);
- if (err) {
- goto unlock;
- }
}
list_push_back(&dpdk_list, &netdev->list_node);
-unlock:
- if (err) {
- rte_free(netdev->tx_q);
- }
ovs_mutex_unlock(&netdev->mutex);
- return err;
+ return 0;
}
static int
@@ -643,6 +636,31 @@ dpdk_dev_parse_name(const char dev_name[], const char prefix[],
return 0;
}
+static void
+dpdk_dev_parse_mtu(const struct smap *args, int *mtu)
+{
+ const char *mtu_str = smap_get(args, "mtu_request");
+ char *end_ptr = NULL;
+ int local_mtu;
+
+ if (!mtu_str) {
+ local_mtu = ETHER_MTU;
+ } else {
+ local_mtu = strtoul(mtu_str, &end_ptr, 0);
+ if (local_mtu < ETHER_MTU ||
+ local_mtu > FRAME_LEN_TO_MTU(NETDEV_DPDK_MAX_FRAME_LEN) ||
+ *end_ptr != '\0') {
+ local_mtu = ETHER_MTU;
+ VLOG_WARN("Invalid mtu_request parameter - defaulting to %d.\n",
+ local_mtu);
+ } else {
+ VLOG_INFO("mtu_request parameter %d detected.\n", local_mtu);
+ }
+ }
+
+ *mtu = local_mtu;
+}
+
static int
vhost_construct_helper(struct netdev *netdev_) OVS_REQUIRES(dpdk_mutex)
{
@@ -773,15 +791,72 @@ 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", netdev->n_txq);
smap_add_format(args, "configured_tx_queues", "%d", dev->real_n_txq);
+ smap_add_format(args, "mtu", "%d", dev->mtu);
ovs_mutex_unlock(&dev->mutex);
return 0;
}
+/* Set the mtu of DPDK_DEV_ETH ports */
+static int
+netdev_dpdk_set_mtu(const struct netdev *netdev, int mtu)
+{
+ struct netdev_dpdk *dev = netdev_dpdk_cast(netdev);
+ int err, dpdk_mtu;
+ uint32_t buf_size;
+ struct dpdk_mp *mp;
+
+ ovs_mutex_lock(&dpdk_mutex);
+ ovs_mutex_lock(&dev->mutex);
+ if (dev->mtu == mtu) {
+ err = 0;
+ goto out;
+ }
+
+ buf_size = dpdk_buf_size(mtu);
+ dpdk_mtu = FRAME_LEN_TO_MTU(buf_size);
+
+ mp = dpdk_mp_get(dev->socket_id, dpdk_mtu);
+ if (!mp) {
+ err = ENOMEM;
+ goto out;
+ }
+
+ rte_eth_dev_stop(dev->port_id);
+
+ dev->dpdk_mp = mp;
+ dev->mtu = mtu;
+ dev->max_packet_len = MTU_TO_FRAME_LEN(dev->mtu);
+
+ err = dpdk_eth_dev_init(dev);
+ if (err) {
+ VLOG_WARN("Unable to set MTU '%d' for '%s'; falling back to default "
+ "MTU '%d'\n", mtu, dev->up.name, ETHER_MTU);
+ dpdk_mp_put(mp);
+ dev->mtu = ETHER_MTU;
+ mp = dpdk_mp_get(dev->socket_id, dev->mtu);
+ if (!mp) {
+ err = ENOMEM;
+ goto out;
+ }
+ dev->dpdk_mp = mp;
+ dev->max_packet_len = MTU_TO_FRAME_LEN(dev->mtu);
+ dpdk_eth_dev_init(dev);
+ goto out;
+ } else {
+ netdev_change_seq_changed(netdev);
+ }
+out:
+ ovs_mutex_unlock(&dev->mutex);
+ ovs_mutex_unlock(&dpdk_mutex);
+ return err;
+}
+
static int
netdev_dpdk_set_config(struct netdev *netdev, const struct smap *args)
{
struct netdev_dpdk *dev = netdev_dpdk_cast(netdev);
+ int mtu;
ovs_mutex_lock(&dev->mutex);
netdev->requested_n_rxq = MAX(smap_get_int(args, "n_rxq",
@@ -789,6 +864,14 @@ netdev_dpdk_set_config(struct netdev *netdev, const struct smap *args)
netdev_change_seq_changed(netdev);
ovs_mutex_unlock(&dev->mutex);
+ dpdk_dev_parse_mtu(args, &mtu);
+
+ if (!dev->mtu) {
+ return netdev_dpdk_set_mtu(netdev, mtu);
+ } else if (mtu != dev->mtu) {
+ VLOG_WARN("Unable to set MTU %d for port %d; this port has immutable MTU "
+ "%d\n", mtu, dev->port_id, dev->mtu);
+ }
return 0;
}
@@ -1407,57 +1490,6 @@ netdev_dpdk_get_mtu(const struct netdev *netdev, int *mtup)
}
static int
-netdev_dpdk_set_mtu(const struct netdev *netdev, int mtu)
-{
- struct netdev_dpdk *dev = netdev_dpdk_cast(netdev);
- int old_mtu, err, dpdk_mtu;
- struct dpdk_mp *old_mp;
- struct dpdk_mp *mp;
- uint32_t buf_size;
-
- ovs_mutex_lock(&dpdk_mutex);
- ovs_mutex_lock(&dev->mutex);
- if (dev->mtu == mtu) {
- err = 0;
- goto out;
- }
-
- buf_size = dpdk_buf_size(mtu);
- dpdk_mtu = FRAME_LEN_TO_MTU(buf_size);
-
- mp = dpdk_mp_get(dev->socket_id, dpdk_mtu);
- if (!mp) {
- err = ENOMEM;
- goto out;
- }
-
- rte_eth_dev_stop(dev->port_id);
-
- old_mtu = dev->mtu;
- old_mp = dev->dpdk_mp;
- dev->dpdk_mp = mp;
- dev->mtu = mtu;
- dev->max_packet_len = MTU_TO_FRAME_LEN(dev->mtu);
-
- err = dpdk_eth_dev_init(dev);
- if (err) {
- dpdk_mp_put(mp);
- dev->mtu = old_mtu;
- dev->dpdk_mp = old_mp;
- dev->max_packet_len = MTU_TO_FRAME_LEN(dev->mtu);
- dpdk_eth_dev_init(dev);
- goto out;
- }
-
- dpdk_mp_put(old_mp);
- netdev_change_seq_changed(netdev);
-out:
- ovs_mutex_unlock(&dev->mutex);
- ovs_mutex_unlock(&dpdk_mutex);
- return err;
-}
-
-static int
netdev_dpdk_get_carrier(const struct netdev *netdev_, bool *carrier);
static int
@@ -2000,6 +2032,61 @@ dpdk_vhost_user_class_init(void)
return 0;
}
+/* Set the mtu of DPDK_DEV_VHOST ports */
+static int
+netdev_dpdk_vhost_set_mtu(const struct netdev *netdev, int mtu)
+{
+ struct netdev_dpdk *dev = netdev_dpdk_cast(netdev);
+ int err = 0;
+ struct dpdk_mp *mp;
+
+ ovs_mutex_lock(&dpdk_mutex);
+ ovs_mutex_lock(&dev->mutex);
+ if (dev->mtu == mtu) {
+ err = 0;
+ goto out;
+ }
+
+ mp = dpdk_mp_get(dev->socket_id, mtu);
+ if (!mp) {
+ err = ENOMEM;
+ goto out;
+ }
+
+ dev->dpdk_mp = mp;
+ dev->mtu = mtu;
+ dev->max_packet_len = MTU_TO_FRAME_LEN(dev->mtu);
+
+ netdev_change_seq_changed(netdev);
+out:
+ ovs_mutex_unlock(&dev->mutex);
+ ovs_mutex_unlock(&dpdk_mutex);
+ return err;
+}
+
+static int
+netdev_dpdk_vhost_set_config(struct netdev *netdev, const struct smap *args)
+{
+ struct netdev_dpdk *dev = netdev_dpdk_cast(netdev);
+ int mtu;
+
+ ovs_mutex_lock(&dev->mutex);
+ netdev->requested_n_rxq = MAX(smap_get_int(args, "n_rxq",
+ netdev->requested_n_rxq), 1);
+ netdev_change_seq_changed(netdev);
+ ovs_mutex_unlock(&dev->mutex);
+
+ dpdk_dev_parse_mtu(args, &mtu);
+
+ if (!dev->mtu) {
+ return netdev_dpdk_vhost_set_mtu(netdev, mtu);
+ } else if (mtu != dev->mtu) {
+ VLOG_WARN("Unable to set MTU %d for vhost port; this port has immutable MTU "
+ "%d\n", mtu, dev->mtu);
+ }
+ return 0;
+}
+
static void
dpdk_common_init(void)
{
@@ -2136,8 +2223,9 @@ unlock_dpdk:
return err;
}
-#define NETDEV_DPDK_CLASS(NAME, INIT, CONSTRUCT, DESTRUCT, MULTIQ, SEND, \
- GET_CARRIER, GET_STATS, GET_FEATURES, GET_STATUS, RXQ_RECV) \
+#define NETDEV_DPDK_CLASS(NAME, INIT, CONSTRUCT, DESTRUCT, SET_CONFIG, \
+ MULTIQ, SEND, SET_MTU, GET_CARRIER, GET_STATS, GET_FEATURES, \
+ GET_STATUS, RXQ_RECV) \
{ \
NAME, \
INIT, /* init */ \
@@ -2149,7 +2237,7 @@ unlock_dpdk:
DESTRUCT, \
netdev_dpdk_dealloc, \
netdev_dpdk_get_config, \
- netdev_dpdk_set_config, \
+ SET_CONFIG , \
NULL, /* get_tunnel_config */ \
NULL, /* build header */ \
NULL, /* push header */ \
@@ -2163,7 +2251,7 @@ unlock_dpdk:
netdev_dpdk_set_etheraddr, \
netdev_dpdk_get_etheraddr, \
netdev_dpdk_get_mtu, \
- netdev_dpdk_set_mtu, \
+ SET_MTU, \
netdev_dpdk_get_ifindex, \
GET_CARRIER, \
netdev_dpdk_get_carrier_resets, \
@@ -2309,8 +2397,10 @@ static const struct netdev_class dpdk_class =
NULL,
netdev_dpdk_construct,
netdev_dpdk_destruct,
+ netdev_dpdk_set_config,
netdev_dpdk_set_multiq,
netdev_dpdk_eth_send,
+ netdev_dpdk_set_mtu,
netdev_dpdk_get_carrier,
netdev_dpdk_get_stats,
netdev_dpdk_get_features,
@@ -2323,8 +2413,10 @@ static const struct netdev_class dpdk_ring_class =
NULL,
netdev_dpdk_ring_construct,
netdev_dpdk_destruct,
+ netdev_dpdk_set_config,
netdev_dpdk_set_multiq,
netdev_dpdk_ring_send,
+ netdev_dpdk_set_mtu,
netdev_dpdk_get_carrier,
netdev_dpdk_get_stats,
netdev_dpdk_get_features,
@@ -2337,8 +2429,10 @@ static const struct netdev_class OVS_UNUSED dpdk_vhost_cuse_class =
dpdk_vhost_cuse_class_init,
netdev_dpdk_vhost_cuse_construct,
netdev_dpdk_vhost_destruct,
+ netdev_dpdk_set_config,
netdev_dpdk_vhost_cuse_set_multiq,
netdev_dpdk_vhost_send,
+ NULL,
netdev_dpdk_vhost_get_carrier,
netdev_dpdk_vhost_get_stats,
NULL,
@@ -2351,8 +2445,10 @@ static const struct netdev_class OVS_UNUSED dpdk_vhost_user_class =
dpdk_vhost_user_class_init,
netdev_dpdk_vhost_user_construct,
netdev_dpdk_vhost_destruct,
+ netdev_dpdk_vhost_set_config,
netdev_dpdk_vhost_set_multiq,
netdev_dpdk_vhost_send,
+ netdev_dpdk_vhost_set_mtu,
netdev_dpdk_vhost_get_carrier,
netdev_dpdk_vhost_get_stats,
NULL,
--
1.9.3
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