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netdev-dpdk: Enable Rx checksum offloading feature on DPDK physical ports.

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Add Rx checksum offloading feature support on DPDK physical ports. By default,
the Rx checksum offloading is enabled if NIC supports. However,
the checksum offloading can be turned OFF either while adding a new DPDK
physical port to OVS or at runtime.

The rx checksum offloading can be turned off by setting the parameter to
'false'. For eg: To disable the rx checksum offloading when adding a port,

     'ovs-vsctl add-port br0 dpdk0 -- \
      set Interface dpdk0 type=dpdk options:rx-checksum-offload=false'

OR (to disable at run time after port is being added to OVS)

    'ovs-vsctl set Interface dpdk0 options:rx-checksum-offload=false'

Similarly to turn ON rx checksum offloading at run time,
    'ovs-vsctl set Interface dpdk0 options:rx-checksum-offload=true'

The Tx checksum offloading support is not implemented due to the following
reasons.

1) Checksum offloading and vectorization are mutually exclusive in DPDK poll
mode driver. Vector packet processing is turned OFF when checksum offloading
is enabled which causes significant performance drop at Tx side.

2) Normally, OVS generates checksum for tunnel packets in software at the
'tunnel push' operation, where the tunnel headers are created. However
enabling Tx checksum offloading involves,

*) Mark every packets for tx checksum offloading at 'tunnel_push' and
recirculate.
*) At the time of xmit, validate the same flag and instruct the NIC to do the
checksum calculation.  In case NIC doesnt support Tx checksum offloading,
the checksum calculation has to be done in software before sending out the
packets.

No significant performance improvement noticed with Tx checksum offloading
due to the e overhead of additional validations + non vector packet processing.
In some test scenarios, it introduces performance drop too.

Rx checksum offloading still offers 8-9% of improvement on VxLAN tunneling
decapsulation even though the SSE vector Rx function is disabled in DPDK poll
mode driver.

Signed-off-by: Sugesh Chandran <sugesh.chandran@intel.com>
Acked-by: Jesse Gross <jesse@kernel.org>
Acked-by: Pravin B Shelar <pshelar@ovn.org>
This commit is contained in:
Sugesh Chandran
2017-01-02 14:27:48 -08:00
committed by Pravin B Shelar
parent 9e0fdb8cdf
commit 1a2bb11817
7 changed files with 144 additions and 14 deletions
Download Patch File Download Diff File Expand all files Collapse all files

50
lib/netdev-dpdk.c
View File

@@ -319,6 +319,10 @@ struct ingress_policer {
rte_spinlock_t policer_lock;
};
enum dpdk_hw_ol_features {
NETDEV_RX_CHECKSUM_OFFLOAD = 1 << 0,
};
struct netdev_dpdk {
struct netdev up;
int port_id;
@@ -384,6 +388,10 @@ struct netdev_dpdk {
/* DPDK-ETH Flow control */
struct rte_eth_fc_conf fc_conf;
/* DPDK-ETH hardware offload features,
* from the enum set 'dpdk_hw_ol_features' */
uint32_t hw_ol_features;
};
struct netdev_rxq_dpdk {
@@ -633,6 +641,8 @@ dpdk_eth_dev_queue_setup(struct netdev_dpdk *dev, int n_rxq, int n_txq)
conf.rxmode.jumbo_frame = 0;
conf.rxmode.max_rx_pkt_len = 0;
}
conf.rxmode.hw_ip_checksum = (dev->hw_ol_features &
NETDEV_RX_CHECKSUM_OFFLOAD) != 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
@@ -692,6 +702,29 @@ dpdk_eth_dev_queue_setup(struct netdev_dpdk *dev, int n_rxq, int n_txq)
return diag;
}
static void
dpdk_eth_checksum_offload_configure(struct netdev_dpdk *dev)
OVS_REQUIRES(dev->mutex)
{
struct rte_eth_dev_info info;
bool rx_csum_ol_flag = false;
uint32_t rx_chksm_offload_capa = DEV_RX_OFFLOAD_UDP_CKSUM |
DEV_RX_OFFLOAD_TCP_CKSUM |
DEV_RX_OFFLOAD_IPV4_CKSUM;
rte_eth_dev_info_get(dev->port_id, &info);
rx_csum_ol_flag = (dev->hw_ol_features & NETDEV_RX_CHECKSUM_OFFLOAD) != 0;
if (rx_csum_ol_flag &&
(info.rx_offload_capa & rx_chksm_offload_capa) !=
rx_chksm_offload_capa) {
VLOG_WARN_ONCE("Rx checksum offload is not supported on device %d",
dev->port_id);
dev->hw_ol_features &= ~NETDEV_RX_CHECKSUM_OFFLOAD;
return;
}
netdev_request_reconfigure(&dev->up);
}
static void
dpdk_eth_flow_ctrl_setup(struct netdev_dpdk *dev) OVS_REQUIRES(dev->mutex)
{
@@ -851,6 +884,9 @@ netdev_dpdk_init(struct netdev *netdev, unsigned int port_no,
/* Initialize the flow control to NULL */
memset(&dev->fc_conf, 0, sizeof dev->fc_conf);
/* Initilize the hardware offload flags to 0 */
dev->hw_ol_features = 0;
if (type == DPDK_DEV_ETH) {
err = dpdk_eth_dev_init(dev);
if (err) {
@@ -1072,6 +1108,9 @@ netdev_dpdk_get_config(const struct netdev *netdev, struct smap *args)
dev->requested_txq_size);
smap_add_format(args, "configured_txq_descriptors", "%d",
dev->txq_size);
if (dev->hw_ol_features & NETDEV_RX_CHECKSUM_OFFLOAD) {
smap_add(args, "rx_csum_offload", "true");
}
}
ovs_mutex_unlock(&dev->mutex);
@@ -1118,6 +1157,8 @@ netdev_dpdk_set_config(struct netdev *netdev, const struct smap *args)
{RTE_FC_NONE, RTE_FC_TX_PAUSE},
{RTE_FC_RX_PAUSE, RTE_FC_FULL }
};
bool rx_chksm_ofld;
bool temp_flag;
ovs_mutex_lock(&dev->mutex);
@@ -1141,6 +1182,15 @@ netdev_dpdk_set_config(struct netdev *netdev, const struct smap *args)
dpdk_eth_flow_ctrl_setup(dev);
}
/* Rx checksum offload configuration */
/* By default the Rx checksum offload is ON */
rx_chksm_ofld = smap_get_bool(args, "rx-checksum-offload", true);
temp_flag = (dev->hw_ol_features & NETDEV_RX_CHECKSUM_OFFLOAD)
!= 0;
if (temp_flag != rx_chksm_ofld) {
dev->hw_ol_features ^= NETDEV_RX_CHECKSUM_OFFLOAD;
dpdk_eth_checksum_offload_configure(dev);
}
ovs_mutex_unlock(&dev->mutex);
return 0;