[dpdk-dev] 回复: [PATCH v2 1/2] net/i40e: improve performance for scalar Tx

[Feifei Wang]

> -----邮件原件-----
> 发件人: Xing, Beilei <beilei.xing at intel.com>
> 发送时间: 2021年6月30日 11:43
> 收件人: Feifei Wang <Feifei.Wang2 at arm.com>
> 抄送: dev at dpdk.org; nd <nd at arm.com>; Ruifeng Wang
> <Ruifeng.Wang at arm.com>
> 主题: RE: [PATCH v2 1/2] net/i40e: improve performance for scalar Tx
> 
> 
> 
> > -----Original Message-----
> > From: Feifei Wang <feifei.wang2 at arm.com>
> > Sent: Wednesday, June 30, 2021 10:04 AM
> > To: Xing, Beilei <beilei.xing at intel.com>
> > Cc: dev at dpdk.org; nd at arm.com; Feifei Wang <feifei.wang2 at arm.com>;
> > Ruifeng Wang <ruifeng.wang at arm.com>
> > Subject: [PATCH v2 1/2] net/i40e: improve performance for scalar Tx
> >
> > For i40e scalar Tx path, if implement FAST_FREE_MBUF mode, it means
> > per- queue all mbufs come from the same mempool and have refcnt = 1.
> >
> > Thus we can use bulk free of the buffers when mbuf fast free mode is
> > enabled.
> >
> > Following are the test results with this patch:
> >
> > MRR L3FWD Test:
> > two ports & bi-directional flows & one core RX API:
> > i40e_recv_pkts_bulk_alloc TX API: i40e_xmit_pkts_simple
> > ring_descs_size = 1024; Ring_I40E_TX_MAX_FREE_SZ = 64; tx_rs_thresh =
> > I40E_DEFAULT_TX_RSBIT_THRESH = 32; tx_free_thresh =
> > I40E_DEFAULT_TX_FREE_THRESH = 32;
> >
> > For scalar path in arm platform with default 'tx_rs_thresh':
> > In n1sdp, performance is improved by 7.9%; In thunderx2, performance
> > is improved by 7.6%.
> >
> > For scalar path in x86 platform with default 'tx_rs_thresh':
> > performance is improved by 4.7%.
> >
> > Suggested-by: Ruifeng Wang <ruifeng.wang at arm.com>
> > Signed-off-by: Feifei Wang <feifei.wang2 at arm.com>
> > Reviewed-by: Ruifeng Wang <ruifeng.wang at arm.com>
> > ---
> >  drivers/net/i40e/i40e_rxtx.c | 26 ++++++++++++++++++++++----
> >  1 file changed, 22 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/net/i40e/i40e_rxtx.c
> > b/drivers/net/i40e/i40e_rxtx.c index 6c58decece..8c72391cde 100644
> > --- a/drivers/net/i40e/i40e_rxtx.c
> > +++ b/drivers/net/i40e/i40e_rxtx.c
> > @@ -1294,7 +1294,11 @@ static __rte_always_inline int
> > i40e_tx_free_bufs(struct i40e_tx_queue *txq)  {
> >  	struct i40e_tx_entry *txep;
> > -	uint16_t i;
> > +	int n = txq->tx_rs_thresh;
> 
> Thanks for the patch, just little comment, can we use 'tx_rs_thresh' to
> replace 'n' to make it more readable?
Good comments for this, I will update it, thanks.

> 
> > +	uint16_t i = 0, j = 0;
> > +	struct rte_mbuf *free[RTE_I40E_TX_MAX_FREE_BUF_SZ];
> > +	const int32_t k = RTE_ALIGN_FLOOR(n,
> > RTE_I40E_TX_MAX_FREE_BUF_SZ);
> > +	const int32_t m = n % RTE_I40E_TX_MAX_FREE_BUF_SZ;
> >
> >  	if ((txq->tx_ring[txq->tx_next_dd].cmd_type_offset_bsz &
> >
> 	rte_cpu_to_le_64(I40E_TXD_QW1_DTYPE_MASK)) != @@ -1307,9
> +1311,23
> > @@ i40e_tx_free_bufs(struct i40e_tx_queue *txq)
> >  		rte_prefetch0((txep + i)->mbuf);
> >
> >  	if (txq->offloads & DEV_TX_OFFLOAD_MBUF_FAST_FREE) {
> > -		for (i = 0; i < txq->tx_rs_thresh; ++i, ++txep) {
> > -			rte_mempool_put(txep->mbuf->pool, txep->mbuf);
> > -			txep->mbuf = NULL;
> > +		if (k) {
> > +			for (j = 0; j != k; j +=
> RTE_I40E_TX_MAX_FREE_BUF_SZ)
> > {
> > +				for (i = 0; i <
> RTE_I40E_TX_MAX_FREE_BUF_SZ;
> > ++i, ++txep) {
> > +					free[i] = txep->mbuf;
> > +					txep->mbuf = NULL;
> > +				}
> > +				rte_mempool_put_bulk(free[0]->pool, (void
> > **)free,
> > +
> > 	RTE_I40E_TX_MAX_FREE_BUF_SZ);
> > +			}
> > +		}
> > +
> > +		if (m) {
> > +			for (i = 0; i < m; ++i, ++txep) {
> > +				free[i] = txep->mbuf;
> > +				txep->mbuf = NULL;
> > +			}
> > +			rte_mempool_put_bulk(free[0]->pool, (void **)free,
> > m);
> >  		}
> >  	} else {
> >  		for (i = 0; i < txq->tx_rs_thresh; ++i, ++txep) {
> > --
> > 2.25.1