On 10/23/2015 10:17 AM, Xie, Huawei wrote:
> 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;
Missed a line
m = __rte_pktmbuf_prefree_seg(m)
> 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);
>>
>>
>
