diff mbox series

[2/4] examples/l3fwd: eliminate unnecessary calculations

Message ID 20210318102550.59265-3-ruifeng.wang@arm.com (mailing list archive)
State Superseded
Delegated to: David Marchand
Headers show
Series l3fwd improvements | expand

Checks

Context Check Description
ci/checkpatch success coding style OK

Commit Message

Ruifeng Wang March 18, 2021, 10:25 a.m. UTC
Both L2 and L3 headers will be used in forward processing. And these
two headers are in the same cache line. It has the same effect for
prefetching with L2 header address and prefetching with L3 header
address.

Changed to use L2 header address for prefetching. The change showed
no measurable performance improvement, but it definitely removed
unnecessary instructions for address calculation.

Signed-off-by: Ruifeng Wang <ruifeng.wang@arm.com>
---
 examples/l3fwd/l3fwd_lpm_neon.h | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

Comments

Jerin Jacob April 13, 2021, 6:40 p.m. UTC | #1
On Thu, Mar 18, 2021 at 3:56 PM Ruifeng Wang <ruifeng.wang@arm.com> wrote:
>
> Both L2 and L3 headers will be used in forward processing. And these
> two headers are in the same cache line. It has the same effect for
> prefetching with L2 header address and prefetching with L3 header
> address.
>
> Changed to use L2 header address for prefetching. The change showed
> no measurable performance improvement, but it definitely removed

Same here.

> unnecessary instructions for address calculation.


>
> Signed-off-by: Ruifeng Wang <ruifeng.wang@arm.com>

Acked-by: Jerin Jacob <jerinj@marvell.com>


> ---
>  examples/l3fwd/l3fwd_lpm_neon.h | 10 +++++-----
>  1 file changed, 5 insertions(+), 5 deletions(-)
>
> diff --git a/examples/l3fwd/l3fwd_lpm_neon.h b/examples/l3fwd/l3fwd_lpm_neon.h
> index ae8840694..1650ae444 100644
> --- a/examples/l3fwd/l3fwd_lpm_neon.h
> +++ b/examples/l3fwd/l3fwd_lpm_neon.h
> @@ -98,14 +98,14 @@ l3fwd_lpm_send_packets(int nb_rx, struct rte_mbuf **pkts_burst,
>         if (k) {
>                 for (i = 0; i < FWDSTEP; i++) {
>                         rte_prefetch0_write(rte_pktmbuf_mtod(pkts_burst[i],
> -                                               struct rte_ether_hdr *) + 1);
> +                                                       void *));
>                 }
>
>                 for (j = 0; j != k - FWDSTEP; j += FWDSTEP) {
>                         for (i = 0; i < FWDSTEP; i++) {
>                                 rte_prefetch0_write(rte_pktmbuf_mtod(
>                                                 pkts_burst[j + i + FWDSTEP],
> -                                               struct rte_ether_hdr *) + 1);
> +                                               void *));
>                         }
>
>                         processx4_step1(&pkts_burst[j], &dip, &ipv4_flag);
> @@ -125,17 +125,17 @@ l3fwd_lpm_send_packets(int nb_rx, struct rte_mbuf **pkts_burst,
>                 switch (m) {
>                 case 3:
>                         rte_prefetch0_write(rte_pktmbuf_mtod(pkts_burst[j],
> -                                               struct rte_ether_hdr *) + 1);
> +                                                       void *));
>                         j++;
>                         /* fallthrough */
>                 case 2:
>                         rte_prefetch0_write(rte_pktmbuf_mtod(pkts_burst[j],
> -                                               struct rte_ether_hdr *) + 1);
> +                                                       void *));
>                         j++;
>                         /* fallthrough */
>                 case 1:
>                         rte_prefetch0_write(rte_pktmbuf_mtod(pkts_burst[j],
> -                                               struct rte_ether_hdr *) + 1);
> +                                                       void *));
>                         j++;
>                 }
>
> --
> 2.25.1
>
diff mbox series

Patch

diff --git a/examples/l3fwd/l3fwd_lpm_neon.h b/examples/l3fwd/l3fwd_lpm_neon.h
index ae8840694..1650ae444 100644
--- a/examples/l3fwd/l3fwd_lpm_neon.h
+++ b/examples/l3fwd/l3fwd_lpm_neon.h
@@ -98,14 +98,14 @@  l3fwd_lpm_send_packets(int nb_rx, struct rte_mbuf **pkts_burst,
 	if (k) {
 		for (i = 0; i < FWDSTEP; i++) {
 			rte_prefetch0_write(rte_pktmbuf_mtod(pkts_burst[i],
-						struct rte_ether_hdr *) + 1);
+							void *));
 		}
 
 		for (j = 0; j != k - FWDSTEP; j += FWDSTEP) {
 			for (i = 0; i < FWDSTEP; i++) {
 				rte_prefetch0_write(rte_pktmbuf_mtod(
 						pkts_burst[j + i + FWDSTEP],
-						struct rte_ether_hdr *) + 1);
+						void *));
 			}
 
 			processx4_step1(&pkts_burst[j], &dip, &ipv4_flag);
@@ -125,17 +125,17 @@  l3fwd_lpm_send_packets(int nb_rx, struct rte_mbuf **pkts_burst,
 		switch (m) {
 		case 3:
 			rte_prefetch0_write(rte_pktmbuf_mtod(pkts_burst[j],
-						struct rte_ether_hdr *) + 1);
+							void *));
 			j++;
 			/* fallthrough */
 		case 2:
 			rte_prefetch0_write(rte_pktmbuf_mtod(pkts_burst[j],
-						struct rte_ether_hdr *) + 1);
+							void *));
 			j++;
 			/* fallthrough */
 		case 1:
 			rte_prefetch0_write(rte_pktmbuf_mtod(pkts_burst[j],
-						struct rte_ether_hdr *) + 1);
+							void *));
 			j++;
 		}