[ovs-dev] [PATCH 1/2] netdev-dpdk: Fix vHost stats.
Ilya Maximets
i.maximets at samsung.com
Thu Aug 18 13:12:34 UTC 2016
On 18.08.2016 15:25, Stokes, Ian wrote:
>> This patch introduces function 'netdev_dpdk_filter_packet_len()' which is
>> intended to find and remove all packets with 'pkt_len > max_packet_len'
>> from the Tx batch.
>>
>> It fixes inaccurate counting of 'tx_bytes' in vHost case if there was
>> dropped packets and allows to simplify send function.
>>
>
> Thanks for the patch Ilya, minor comment below.
>
>> Fixes: 0072e931b207 ("netdev-dpdk: add support for jumbo frames")
>> Signed-off-by: Ilya Maximets <i.maximets at samsung.com>
>> ---
>> lib/netdev-dpdk.c | 52 +++++++++++++++++++++++++++++---------------------
>> --
>> 1 file changed, 29 insertions(+), 23 deletions(-)
>>
>> diff --git a/lib/netdev-dpdk.c b/lib/netdev-dpdk.c index e5f2cdd..bd374d0
>> 100644
>> --- a/lib/netdev-dpdk.c
>> +++ b/lib/netdev-dpdk.c
>> @@ -1435,6 +1435,28 @@ netdev_dpdk_qos_run__(struct netdev_dpdk *dev,
>> struct rte_mbuf **pkts,
>> return cnt;
>> }
>>
>> +static int
>> +netdev_dpdk_filter_packet_len(struct netdev_dpdk *dev, struct rte_mbuf
>> **pkts,
>> + int pkt_cnt) {
>> + int i = 0;
>> + int cnt = 0;
>> + struct rte_mbuf *pkt;
>> +
>> + for (i = 0; i < pkt_cnt; i++) {
>> + pkt = pkts[i];
>> + if (OVS_UNLIKELY(pkt->pkt_len > dev->max_packet_len)) {
>> + VLOG_WARN_RL(&rl, "%s: Too big size %" PRIu32 "
>> max_packet_len %d",
>> + dev->up.name, pkt->pkt_len, dev-
>>> max_packet_len);
>> + rte_pktmbuf_free(pkt);
>> + } else if (i != cnt++) {
>> + pkts[cnt - 1] = pkt;
>> + }
>> + }
>> +
>> + return cnt;
>> +}
>> +
>> static inline void
>> netdev_dpdk_vhost_update_tx_counters(struct netdev_stats *stats,
>> struct dp_packet **packets, @@ -
>> 1459,8 +1481,7 @@ __netdev_dpdk_vhost_send(struct netdev *netdev, int qid,
>> struct netdev_dpdk *dev = netdev_dpdk_cast(netdev);
>> struct rte_mbuf **cur_pkts = (struct rte_mbuf **) pkts;
>> unsigned int total_pkts = cnt;
>> - unsigned int qos_pkts = 0;
>> - unsigned int mtu_dropped = 0;
>> + unsigned int dropped = 0;
>> int i, retries = 0;
>>
>> qid = dev->tx_q[qid % netdev->n_txq].map; @@ -1477,50 +1498,35 @@
>> __netdev_dpdk_vhost_send(struct netdev *netdev, int qid,
>>
>> /* Check has QoS has been configured for the netdev */
>> cnt = netdev_dpdk_qos_run__(dev, cur_pkts, cnt);
>> - qos_pkts = total_pkts - cnt;
>
> I think it would be better to call netdev_dpdk_filter_packet_len() before netdev_dpdk_qos_run__ above.
> If the packet is too large for the netdev it will be dropped inevitably, we should avoid the overhead of QoS before dropping it, thoughts?
Sounds reasonable. I'll send v2.
>> + cnt = netdev_dpdk_filter_packet_len(dev, cur_pkts, cnt);
>> + dropped = total_pkts - cnt;
>>
>> do {
>> int vhost_qid = qid * VIRTIO_QNUM + VIRTIO_RXQ;
>> unsigned int tx_pkts;
>> - unsigned int try_tx_pkts = cnt;
>>
>> - for (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,
>> try_tx_pkts);
>> + vhost_qid, cur_pkts, cnt);
>> 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);
>> netdev_dpdk_vhost_update_tx_counters(&dev->stats, pkts, total_pkts,
>> - cnt + mtu_dropped + qos_pkts);
>> + cnt + dropped);
>> rte_spinlock_unlock(&dev->stats_lock);
>>
>> out:
>> - for (i = 0; i < total_pkts - qos_pkts; i++) {
>> + for (i = 0; i < total_pkts - dropped; i++) {
>> dp_packet_delete(pkts[i]);
>> }
>> }
>> --
>> 2.7.4
>>
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