On 10/23/2015 12:57 AM, Stephen Hemminger wrote:
> On Thu, 22 Oct 2015 20:09:50 +0800
> Huawei Xie <huawei.xie at intel.com> wrote:
>
>> Changes in v4:
>> - move virtio_xmit_cleanup ahead to free descriptors earlier
>>
>> Changes in v3:
>> - Remove return at the end of void function
>> - Remove always_inline attribute for virtio_xmit_cleanup
>> bulk free of mbufs when clean used ring.
>> shift operation of idx could be saved if vq_free_cnt means
>> free slots rather than free descriptors.
>>
>> TODO: rearrange vq data structure, pack the stats var together so that we
>> could use one vec instruction to update all of them.
>>
>> Signed-off-by: Huawei Xie <huawei.xie at intel.com>
>> ---
>> drivers/net/virtio/virtio_ethdev.h | 3 ++
>> drivers/net/virtio/virtio_rxtx_simple.c | 93
>> +++++++++++++++++++++++++++++++++
>> 2 files changed, 96 insertions(+)
>>
>> diff --git a/drivers/net/virtio/virtio_ethdev.h
>> b/drivers/net/virtio/virtio_ethdev.h
>> index d7797ab..ae2d47d 100644
>> --- a/drivers/net/virtio/virtio_ethdev.h
>> +++ b/drivers/net/virtio/virtio_ethdev.h
>> @@ -111,6 +111,9 @@ uint16_t virtio_xmit_pkts(void *tx_queue, struct
>> rte_mbuf **tx_pkts,
>> uint16_t virtio_recv_pkts_vec(void *rx_queue, struct rte_mbuf **rx_pkts,
>> uint16_t nb_pkts);
>>
>> +uint16_t virtio_xmit_pkts_simple(void *tx_queue, struct rte_mbuf **tx_pkts,
>> + uint16_t nb_pkts);
>> +
>> /*
>> * The VIRTIO_NET_F_GUEST_TSO[46] features permit the host to send us
>> * frames larger than 1514 bytes. We do not yet support software LRO
>> diff --git a/drivers/net/virtio/virtio_rxtx_simple.c
>> b/drivers/net/virtio/virtio_rxtx_simple.c
>> index ef17562..79b4f7f 100644
>> --- a/drivers/net/virtio/virtio_rxtx_simple.c
>> +++ b/drivers/net/virtio/virtio_rxtx_simple.c
>> @@ -288,6 +288,99 @@ virtio_recv_pkts_vec(void *rx_queue, struct rte_mbuf
>> **rx_pkts,
>> return nb_pkts_received;
>> }
>>
>> +#define VIRTIO_TX_FREE_THRESH 32
>> +#define VIRTIO_TX_MAX_FREE_BUF_SZ 32
>> +#define VIRTIO_TX_FREE_NR 32
>> +/* TODO: vq->tx_free_cnt could mean num of free slots so we could avoid
>> shift */
>> +static inline void
>> +virtio_xmit_cleanup(struct virtqueue *vq)
>> +{
>> + uint16_t i, desc_idx;
>> + int nb_free = 0;
>> + struct rte_mbuf *m, *free[VIRTIO_TX_MAX_FREE_BUF_SZ];
>> +
>> + desc_idx = (uint16_t)(vq->vq_used_cons_idx &
>> + ((vq->vq_nentries >> 1) - 1));
>> + free[0] = (struct rte_mbuf *)vq->vq_descx[desc_idx++].cookie;
>> + nb_free = 1;
>> +
>> + for (i = 1; i < VIRTIO_TX_FREE_NR; i++) {
>> + m = (struct rte_mbuf *)vq->vq_descx[desc_idx++].cookie;
>> + if (likely(m->pool == free[0]->pool))
>> + free[nb_free++] = m;
>> + else {
>> + rte_mempool_put_bulk(free[0]->pool, (void **)free,
>> + nb_free);
>> + free[0] = m;
>> + nb_free = 1;
>> + }
>> + }
>> +
>> + rte_mempool_put_bulk(free[0]->pool, (void **)free, nb_free);
>> + vq->vq_used_cons_idx += VIRTIO_TX_FREE_NR;
>> + vq->vq_free_cnt += (VIRTIO_TX_FREE_NR << 1);
>> +}
> I think you need to handle refcount, here is a similar patch
> for ixgbe.
ok, like this:
m = (struct rte_mbuf *)vq->vq_descx[desc_idx++].cookie;
if (likely(m != NULL)) {
...
>
> Subject: ixgbe: speed up transmit
>
> Coalesce transmit buffers and put them back into the pool
> in one burst.
>
> Signed-off-by: Stephen Hemminger <stephen at networkplumber.org>
>
> --- a/lib/librte_pmd_ixgbe/ixgbe_rxtx.c
> +++ b/lib/librte_pmd_ixgbe/ixgbe_rxtx.c
> @@ -120,12 +120,16 @@ rte_rxmbuf_alloc(struct rte_mempool *mp)
> * Check for descriptors with their DD bit set and free mbufs.
> * Return the total number of buffers freed.
> */
> +#define TX_FREE_BULK 32
> +
> static inline int __attribute__((always_inline))
> ixgbe_tx_free_bufs(struct ixgbe_tx_queue *txq)
> {
> struct ixgbe_tx_entry *txep;
> uint32_t status;
> - int i;
> + int i, n = 0;
> + struct rte_mempool *txpool = NULL;
> + struct rte_mbuf *free_list[TX_FREE_BULK];
>
> /* check DD bit on threshold descriptor */
> status = txq->tx_ring[txq->tx_next_dd].wb.status;
> @@ -138,20 +142,26 @@ ixgbe_tx_free_bufs(struct ixgbe_tx_queue
> */
> txep = &(txq->sw_ring[txq->tx_next_dd - (txq->tx_rs_thresh - 1)]);
>
> - /* free buffers one at a time */
> - if ((txq->txq_flags & (uint32_t)ETH_TXQ_FLAGS_NOREFCOUNT) != 0) {
> - for (i = 0; i < txq->tx_rs_thresh; ++i, ++txep) {
> - txep->mbuf->next = NULL;
> - rte_mempool_put(txep->mbuf->pool, txep->mbuf);
> - txep->mbuf = NULL;
> - }
> - } else {
> - for (i = 0; i < txq->tx_rs_thresh; ++i, ++txep) {
> - rte_pktmbuf_free_seg(txep->mbuf);
> - txep->mbuf = NULL;
> + for (i = 0; i < txq->tx_rs_thresh; ++i, ++txep) {
> + struct rte_mbuf *m;
> +
> + /* free buffers one at a time */
> + m = __rte_pktmbuf_prefree_seg(txep->mbuf);
> + txep->mbuf = NULL;
> +
> + if (n >= TX_FREE_BULK ||
check whether m is NULL here.
> + (n > 0 && m->pool != txpool)) {
> + rte_mempool_put_bulk(txpool, (void **)free_list, n);
> + n = 0;
> }
> +
> + txpool = m->pool;
> + free_list[n++] = m;
> }
>
> + if (n > 0)
> + rte_mempool_put_bulk(txpool, (void **)free_list, n);
> +
> /* buffers were freed, update counters */
> txq->nb_tx_free = (uint16_t)(txq->nb_tx_free + txq->tx_rs_thresh);
> txq->tx_next_dd = (uint16_t)(txq->tx_next_dd + txq->tx_rs_thresh);
>
>
