[dpdk-dev,v2] ixgbe: remove vector pmd burst size restriction
Commit Message
On receive side, the burst size now floor aligns to RTE_IXGBE_DESCS_PER_LOOP power of 2.
According to this rule, the burst size less than 4 still won't receive anything.
(Before this change, the burst size less than 32 can't receive anything.)
_recv_*_pkts_vec returns no more than 32(RTE_IXGBE_RXQ_REARM_THRESH) packets.
On transmit side, the max burst size no longer bind with a constant, however it still
require to check the cross tx_rs_thresh violation.
There's no obvious performance drop found on both recv_pkts_vec
and recv_scattered_pkts_vec on burst size 32.
Signed-off-by: Cunming Liang <cunming.liang@intel.com>
---
v2 change:
- keep max rx burst size in 32
- reword some comments
drivers/net/ixgbe/ixgbe_rxtx.c | 4 +++-
drivers/net/ixgbe/ixgbe_rxtx.h | 5 ++---
drivers/net/ixgbe/ixgbe_rxtx_vec.c | 39 +++++++++++++++++++++-----------------
3 files changed, 27 insertions(+), 21 deletions(-)
Comments
On 04/08/15 08:32, Cunming Liang wrote:
> On receive side, the burst size now floor aligns to RTE_IXGBE_DESCS_PER_LOOP power of 2.
> According to this rule, the burst size less than 4 still won't receive anything.
> (Before this change, the burst size less than 32 can't receive anything.)
> _recv_*_pkts_vec returns no more than 32(RTE_IXGBE_RXQ_REARM_THRESH) packets.
>
> On transmit side, the max burst size no longer bind with a constant, however it still
> require to check the cross tx_rs_thresh violation.
>
> There's no obvious performance drop found on both recv_pkts_vec
> and recv_scattered_pkts_vec on burst size 32.
>
> Signed-off-by: Cunming Liang <cunming.liang@intel.com>
> ---
> v2 change:
> - keep max rx burst size in 32
> - reword some comments
>
> drivers/net/ixgbe/ixgbe_rxtx.c | 4 +++-
> drivers/net/ixgbe/ixgbe_rxtx.h | 5 ++---
> drivers/net/ixgbe/ixgbe_rxtx_vec.c | 39 +++++++++++++++++++++-----------------
> 3 files changed, 27 insertions(+), 21 deletions(-)
>
> diff --git a/drivers/net/ixgbe/ixgbe_rxtx.c b/drivers/net/ixgbe/ixgbe_rxtx.c
> index 91023b9..d06aaae 100644
> --- a/drivers/net/ixgbe/ixgbe_rxtx.c
> +++ b/drivers/net/ixgbe/ixgbe_rxtx.c
> @@ -4008,7 +4008,9 @@ ixgbe_set_rx_function(struct rte_eth_dev *dev)
> */
> } else if (adapter->rx_vec_allowed) {
> PMD_INIT_LOG(DEBUG, "Vector rx enabled, please make sure RX "
> - "burst size no less than 32.");
> + "burst size no less than "
> + "RTE_IXGBE_DESCS_PER_LOOP(=4) (port=%d).",
I think you should write in this line:
"%d (port=%d)", RTE_IXGBE_DESCS_PER_LOOP,
> + dev->data->port_id);
>
> dev->rx_pkt_burst = ixgbe_recv_pkts_vec;
> } else if (adapter->rx_bulk_alloc_allowed) {
> diff --git a/drivers/net/ixgbe/ixgbe_rxtx.h b/drivers/net/ixgbe/ixgbe_rxtx.h
> index 113682a..b9eca67 100644
> --- a/drivers/net/ixgbe/ixgbe_rxtx.h
> +++ b/drivers/net/ixgbe/ixgbe_rxtx.h
> @@ -47,9 +47,8 @@
> (uint64_t) ((mb)->buf_physaddr + RTE_PKTMBUF_HEADROOM)
>
> #ifdef RTE_IXGBE_INC_VECTOR
> -#define RTE_IXGBE_VPMD_RX_BURST 32
> -#define RTE_IXGBE_VPMD_TX_BURST 32
> -#define RTE_IXGBE_RXQ_REARM_THRESH RTE_IXGBE_VPMD_RX_BURST
> +#define RTE_IXGBE_RXQ_REARM_THRESH 32
> +#define RTE_IXGBE_MAX_RX_BURST RTE_IXGBE_RXQ_REARM_THRESH
> #define RTE_IXGBE_TX_MAX_FREE_BUF_SZ 64
> #endif
>
> diff --git a/drivers/net/ixgbe/ixgbe_rxtx_vec.c b/drivers/net/ixgbe/ixgbe_rxtx_vec.c
> index cf25a53..2ca0e4c 100644
> --- a/drivers/net/ixgbe/ixgbe_rxtx_vec.c
> +++ b/drivers/net/ixgbe/ixgbe_rxtx_vec.c
> @@ -245,13 +245,13 @@ desc_to_olflags_v(__m128i descs[4], struct rte_mbuf **rx_pkts)
> #endif
>
> /*
> - * vPMD receive routine, now only accept (nb_pkts == RTE_IXGBE_VPMD_RX_BURST)
> - * in one loop
> + * vPMD raw receive routine, only accept(nb_pkts >= RTE_IXGBE_DESCS_PER_LOOP)
> *
> * Notice:
> - * - nb_pkts < RTE_IXGBE_VPMD_RX_BURST, just return no packet
> - * - nb_pkts > RTE_IXGBE_VPMD_RX_BURST, only scan RTE_IXGBE_VPMD_RX_BURST
> + * - nb_pkts < RTE_IXGBE_DESCS_PER_LOOP, just return no packet
> + * - nb_pkts > RTE_IXGBE_MAX_RX_BURST, only scan RTE_IXGBE_MAX_RX_BURST
> * numbers of DD bit
> + * - floor align nb_pkts to a RTE_IXGBE_DESC_PER_LOOP power-of-two
> * - don't support ol_flags for rss and csum err
> */
> static inline uint16_t
> @@ -286,8 +286,11 @@ _recv_raw_pkts_vec(struct ixgbe_rx_queue *rxq, struct rte_mbuf **rx_pkts,
> __m128i dd_check, eop_check;
> #endif /* RTE_NEXT_ABI */
>
> - if (unlikely(nb_pkts < RTE_IXGBE_VPMD_RX_BURST))
> - return 0;
> + /* nb_pkts shall be less equal than RTE_IXGBE_MAX_RX_BURST */
> + nb_pkts = RTE_MIN(nb_pkts, RTE_IXGBE_MAX_RX_BURST);
> +
> + /* nb_pkts has to be floor-aligned to RTE_IXGBE_DESCS_PER_LOOP */
> + nb_pkts = RTE_ALIGN_FLOOR(nb_pkts, RTE_IXGBE_DESCS_PER_LOOP);
>
> /* Just the act of getting into the function from the application is
> * going to cost about 7 cycles */
> @@ -356,7 +359,7 @@ _recv_raw_pkts_vec(struct ixgbe_rx_queue *rxq, struct rte_mbuf **rx_pkts,
> * D. fill info. from desc to mbuf
> */
> #endif /* RTE_NEXT_ABI */
> - for (pos = 0, nb_pkts_recd = 0; pos < RTE_IXGBE_VPMD_RX_BURST;
> + for (pos = 0, nb_pkts_recd = 0; pos < nb_pkts;
> pos += RTE_IXGBE_DESCS_PER_LOOP,
> rxdp += RTE_IXGBE_DESCS_PER_LOOP) {
> #ifdef RTE_NEXT_ABI
> @@ -518,13 +521,13 @@ _recv_raw_pkts_vec(struct ixgbe_rx_queue *rxq, struct rte_mbuf **rx_pkts,
> }
>
> /*
> - * vPMD receive routine, now only accept (nb_pkts == RTE_IXGBE_VPMD_RX_BURST)
> - * in one loop
> + * vPMD receive routine, only accept(nb_pkts >= RTE_IXGBE_DESCS_PER_LOOP)
> *
> * Notice:
> - * - nb_pkts < RTE_IXGBE_VPMD_RX_BURST, just return no packet
> - * - nb_pkts > RTE_IXGBE_VPMD_RX_BURST, only scan RTE_IXGBE_VPMD_RX_BURST
> + * - nb_pkts < RTE_IXGBE_DESCS_PER_LOOP, just return no packet
> + * - nb_pkts > RTE_IXGBE_MAX_RX_BURST, only scan RTE_IXGBE_MAX_RX_BURST
> * numbers of DD bit
> + * - floor align nb_pkts to a RTE_IXGBE_DESC_PER_LOOP power-of-two
> * - don't support ol_flags for rss and csum err
> */
> uint16_t
> @@ -538,12 +541,11 @@ static inline uint16_t
> reassemble_packets(struct ixgbe_rx_queue *rxq, struct rte_mbuf **rx_bufs,
> uint16_t nb_bufs, uint8_t *split_flags)
> {
> - struct rte_mbuf *pkts[RTE_IXGBE_VPMD_RX_BURST]; /*finished pkts*/
> + struct rte_mbuf *pkts[nb_bufs]; /*finished pkts*/
> struct rte_mbuf *start = rxq->pkt_first_seg;
> struct rte_mbuf *end = rxq->pkt_last_seg;
> unsigned pkt_idx, buf_idx;
>
> -
> for (buf_idx = 0, pkt_idx = 0; buf_idx < nb_bufs; buf_idx++) {
> if (end != NULL) {
> /* processing a split packet */
> @@ -603,14 +605,17 @@ reassemble_packets(struct ixgbe_rx_queue *rxq, struct rte_mbuf **rx_bufs,
> *
> * Notice:
> * - don't support ol_flags for rss and csum err
> - * - now only accept (nb_pkts == RTE_IXGBE_VPMD_RX_BURST)
> + * - nb_pkts < RTE_IXGBE_DESCS_PER_LOOP, just return no packet
> + * - nb_pkts > RTE_IXGBE_MAX_RX_BURST, only scan RTE_IXGBE_MAX_RX_BURST
> + * numbers of DD bit
> + * - floor align nb_pkts to a RTE_IXGBE_DESC_PER_LOOP power-of-two
> */
> uint16_t
> ixgbe_recv_scattered_pkts_vec(void *rx_queue, struct rte_mbuf **rx_pkts,
> uint16_t nb_pkts)
> {
> struct ixgbe_rx_queue *rxq = rx_queue;
> - uint8_t split_flags[RTE_IXGBE_VPMD_RX_BURST] = {0};
> + uint8_t split_flags[RTE_IXGBE_MAX_RX_BURST] = {0};
>
> /* get some new buffers */
> uint16_t nb_bufs = _recv_raw_pkts_vec(rxq, rx_pkts, nb_pkts,
I don't know if it actually matters from performance point of view, but
you check the whole split_flags array, even if you received only 4
packets. Though the overhead of the a for loop might be bigger.
> @@ -735,8 +740,8 @@ ixgbe_xmit_pkts_vec(void *tx_queue, struct rte_mbuf **tx_pkts,
> uint64_t rs = IXGBE_ADVTXD_DCMD_RS|DCMD_DTYP_FLAGS;
> int i;
>
> - if (unlikely(nb_pkts > RTE_IXGBE_VPMD_TX_BURST))
> - nb_pkts = RTE_IXGBE_VPMD_TX_BURST;
> + /* cross rx_thresh boundary is not allowed */
> + nb_pkts = RTE_MIN(nb_pkts, txq->tx_rs_thresh);
>
> if (txq->nb_tx_free < txq->tx_free_thresh)
> ixgbe_tx_free_bufs(txq);
>
Hi Zoltan,
> > } else if (adapter->rx_vec_allowed) {
> > PMD_INIT_LOG(DEBUG, "Vector rx enabled, please make sure RX "
> > - "burst size no less than 32.");
> > + "burst size no less than "
> > + "RTE_IXGBE_DESCS_PER_LOOP(=4) (port=%d).",
>
> I think you should write in this line:
>
> "%d (port=%d)", RTE_IXGBE_DESCS_PER_LOOP,
> > + dev->data->port_id);
> >
Ok, it looks better, will take it.
[...]
> > uint16_t
> > ixgbe_recv_scattered_pkts_vec(void *rx_queue, struct rte_mbuf **rx_pkts,
> > uint16_t nb_pkts)
> > {
> > struct ixgbe_rx_queue *rxq = rx_queue;
> > - uint8_t split_flags[RTE_IXGBE_VPMD_RX_BURST] = {0};
> > + uint8_t split_flags[RTE_IXGBE_MAX_RX_BURST] = {0};
> >
> > /* get some new buffers */
> > uint16_t nb_bufs = _recv_raw_pkts_vec(rxq, rx_pkts, nb_pkts,
>
> I don't know if it actually matters from performance point of view, but
> you check the whole split_flags array, even if you received only 4
> packets. Though the overhead of the a for loop might be bigger.
>
v2 here just roll back the change.
The size of array is constant. It won't loop much, always compare 4 times 'split_fl64[]==0'.
As you said, I ever sent another variable aplit_flags with loop, only very tiny performance difference.
As the patch is not trying to improve the performance here, any improvement I propose to make it in another patch.
@@ -4008,7 +4008,9 @@ ixgbe_set_rx_function(struct rte_eth_dev *dev)
*/
} else if (adapter->rx_vec_allowed) {
PMD_INIT_LOG(DEBUG, "Vector rx enabled, please make sure RX "
- "burst size no less than 32.");
+ "burst size no less than "
+ "RTE_IXGBE_DESCS_PER_LOOP(=4) (port=%d).",
+ dev->data->port_id);
dev->rx_pkt_burst = ixgbe_recv_pkts_vec;
} else if (adapter->rx_bulk_alloc_allowed) {
@@ -47,9 +47,8 @@
(uint64_t) ((mb)->buf_physaddr + RTE_PKTMBUF_HEADROOM)
#ifdef RTE_IXGBE_INC_VECTOR
-#define RTE_IXGBE_VPMD_RX_BURST 32
-#define RTE_IXGBE_VPMD_TX_BURST 32
-#define RTE_IXGBE_RXQ_REARM_THRESH RTE_IXGBE_VPMD_RX_BURST
+#define RTE_IXGBE_RXQ_REARM_THRESH 32
+#define RTE_IXGBE_MAX_RX_BURST RTE_IXGBE_RXQ_REARM_THRESH
#define RTE_IXGBE_TX_MAX_FREE_BUF_SZ 64
#endif
@@ -245,13 +245,13 @@ desc_to_olflags_v(__m128i descs[4], struct rte_mbuf **rx_pkts)
#endif
/*
- * vPMD receive routine, now only accept (nb_pkts == RTE_IXGBE_VPMD_RX_BURST)
- * in one loop
+ * vPMD raw receive routine, only accept(nb_pkts >= RTE_IXGBE_DESCS_PER_LOOP)
*
* Notice:
- * - nb_pkts < RTE_IXGBE_VPMD_RX_BURST, just return no packet
- * - nb_pkts > RTE_IXGBE_VPMD_RX_BURST, only scan RTE_IXGBE_VPMD_RX_BURST
+ * - nb_pkts < RTE_IXGBE_DESCS_PER_LOOP, just return no packet
+ * - nb_pkts > RTE_IXGBE_MAX_RX_BURST, only scan RTE_IXGBE_MAX_RX_BURST
* numbers of DD bit
+ * - floor align nb_pkts to a RTE_IXGBE_DESC_PER_LOOP power-of-two
* - don't support ol_flags for rss and csum err
*/
static inline uint16_t
@@ -286,8 +286,11 @@ _recv_raw_pkts_vec(struct ixgbe_rx_queue *rxq, struct rte_mbuf **rx_pkts,
__m128i dd_check, eop_check;
#endif /* RTE_NEXT_ABI */
- if (unlikely(nb_pkts < RTE_IXGBE_VPMD_RX_BURST))
- return 0;
+ /* nb_pkts shall be less equal than RTE_IXGBE_MAX_RX_BURST */
+ nb_pkts = RTE_MIN(nb_pkts, RTE_IXGBE_MAX_RX_BURST);
+
+ /* nb_pkts has to be floor-aligned to RTE_IXGBE_DESCS_PER_LOOP */
+ nb_pkts = RTE_ALIGN_FLOOR(nb_pkts, RTE_IXGBE_DESCS_PER_LOOP);
/* Just the act of getting into the function from the application is
* going to cost about 7 cycles */
@@ -356,7 +359,7 @@ _recv_raw_pkts_vec(struct ixgbe_rx_queue *rxq, struct rte_mbuf **rx_pkts,
* D. fill info. from desc to mbuf
*/
#endif /* RTE_NEXT_ABI */
- for (pos = 0, nb_pkts_recd = 0; pos < RTE_IXGBE_VPMD_RX_BURST;
+ for (pos = 0, nb_pkts_recd = 0; pos < nb_pkts;
pos += RTE_IXGBE_DESCS_PER_LOOP,
rxdp += RTE_IXGBE_DESCS_PER_LOOP) {
#ifdef RTE_NEXT_ABI
@@ -518,13 +521,13 @@ _recv_raw_pkts_vec(struct ixgbe_rx_queue *rxq, struct rte_mbuf **rx_pkts,
}
/*
- * vPMD receive routine, now only accept (nb_pkts == RTE_IXGBE_VPMD_RX_BURST)
- * in one loop
+ * vPMD receive routine, only accept(nb_pkts >= RTE_IXGBE_DESCS_PER_LOOP)
*
* Notice:
- * - nb_pkts < RTE_IXGBE_VPMD_RX_BURST, just return no packet
- * - nb_pkts > RTE_IXGBE_VPMD_RX_BURST, only scan RTE_IXGBE_VPMD_RX_BURST
+ * - nb_pkts < RTE_IXGBE_DESCS_PER_LOOP, just return no packet
+ * - nb_pkts > RTE_IXGBE_MAX_RX_BURST, only scan RTE_IXGBE_MAX_RX_BURST
* numbers of DD bit
+ * - floor align nb_pkts to a RTE_IXGBE_DESC_PER_LOOP power-of-two
* - don't support ol_flags for rss and csum err
*/
uint16_t
@@ -538,12 +541,11 @@ static inline uint16_t
reassemble_packets(struct ixgbe_rx_queue *rxq, struct rte_mbuf **rx_bufs,
uint16_t nb_bufs, uint8_t *split_flags)
{
- struct rte_mbuf *pkts[RTE_IXGBE_VPMD_RX_BURST]; /*finished pkts*/
+ struct rte_mbuf *pkts[nb_bufs]; /*finished pkts*/
struct rte_mbuf *start = rxq->pkt_first_seg;
struct rte_mbuf *end = rxq->pkt_last_seg;
unsigned pkt_idx, buf_idx;
-
for (buf_idx = 0, pkt_idx = 0; buf_idx < nb_bufs; buf_idx++) {
if (end != NULL) {
/* processing a split packet */
@@ -603,14 +605,17 @@ reassemble_packets(struct ixgbe_rx_queue *rxq, struct rte_mbuf **rx_bufs,
*
* Notice:
* - don't support ol_flags for rss and csum err
- * - now only accept (nb_pkts == RTE_IXGBE_VPMD_RX_BURST)
+ * - nb_pkts < RTE_IXGBE_DESCS_PER_LOOP, just return no packet
+ * - nb_pkts > RTE_IXGBE_MAX_RX_BURST, only scan RTE_IXGBE_MAX_RX_BURST
+ * numbers of DD bit
+ * - floor align nb_pkts to a RTE_IXGBE_DESC_PER_LOOP power-of-two
*/
uint16_t
ixgbe_recv_scattered_pkts_vec(void *rx_queue, struct rte_mbuf **rx_pkts,
uint16_t nb_pkts)
{
struct ixgbe_rx_queue *rxq = rx_queue;
- uint8_t split_flags[RTE_IXGBE_VPMD_RX_BURST] = {0};
+ uint8_t split_flags[RTE_IXGBE_MAX_RX_BURST] = {0};
/* get some new buffers */
uint16_t nb_bufs = _recv_raw_pkts_vec(rxq, rx_pkts, nb_pkts,
@@ -735,8 +740,8 @@ ixgbe_xmit_pkts_vec(void *tx_queue, struct rte_mbuf **tx_pkts,
uint64_t rs = IXGBE_ADVTXD_DCMD_RS|DCMD_DTYP_FLAGS;
int i;
- if (unlikely(nb_pkts > RTE_IXGBE_VPMD_TX_BURST))
- nb_pkts = RTE_IXGBE_VPMD_TX_BURST;
+ /* cross rx_thresh boundary is not allowed */
+ nb_pkts = RTE_MIN(nb_pkts, txq->tx_rs_thresh);
if (txq->nb_tx_free < txq->tx_free_thresh)
ixgbe_tx_free_bufs(txq);