> -----Original Message-----
> From: dev [mailto:dev-boun...@openvswitch.org] On Behalf Of Ethan Jackson
> Sent: Monday, May 18, 2015 5:08 PM
> To: dev@openvswitch.org
> Subject: Re: [ovs-dev] [PATCH] dpdk: Ditch MAX_PKT_BURST macro.
>
> This version of the patch breaks sparse, I sent out another.
>
> Ethan
The change makes sense - I tested this version on various dpdk interfaces and
as expected there was no performance issues.
>
> On Sat, May 16, 2015 at 11:24 AM, Ethan Jackson <et...@nicira.com> wrote:
> > The MAX_PKT_BURST and NETDEV_MAX_RX_BATCH macros had a confusing
> > relationship. They basically purport to do the same thing, making it
> > unclear which is the source of truth.
> >
> > Furthermore, while NETDEV_MAX_RX_BATCH was 256, MAX_PKT_BURST was 32,
> > meaning we never process a batch larger than 32 packets further adding
> > to the confusion.
> >
> > This patch resolves the issue by removing MAX_PKT_BURST completely,
> > and shrinking the new NETDEV_MAX_BURST macro to only 32. This should
> > have no change in the execution path except shrinking a couple of
> > structs and memory allocations (can't hurt).
> >
> > Signed-off-by: Ethan Jackson <et...@nicira.com>
> > ---
> > lib/dpif-netdev.c | 10 +++++-----
> > lib/netdev-dpdk.c | 7 ++-----
> > lib/netdev.h | 2 +-
> > 3 files changed, 8 insertions(+), 11 deletions(-)
> >
> > diff --git a/lib/dpif-netdev.c b/lib/dpif-netdev.c
> > index f1d65f5..4216865 100644
> > --- a/lib/dpif-netdev.c
> > +++ b/lib/dpif-netdev.c
> > @@ -2500,7 +2500,7 @@ dp_netdev_process_rxq_port(struct
> dp_netdev_pmd_thread *pmd,
> > struct dp_netdev_port *port,
> > struct netdev_rxq *rxq)
> > {
> > - struct dp_packet *packets[NETDEV_MAX_RX_BATCH];
> > + struct dp_packet *packets[NETDEV_MAX_BURST];
> > int error, cnt;
> >
> > cycles_count_start(pmd);
> > @@ -3027,7 +3027,7 @@ struct packet_batch {
> >
> > struct dp_netdev_flow *flow;
> >
> > - struct dp_packet *packets[NETDEV_MAX_RX_BATCH];
> > + struct dp_packet *packets[NETDEV_MAX_BURST];
> > };
> >
> > static inline void
> > @@ -3397,7 +3397,7 @@ dp_execute_cb(void *aux_, struct dp_packet **packets,
> int cnt,
> >
> > case OVS_ACTION_ATTR_TUNNEL_PUSH:
> > if (*depth < MAX_RECIRC_DEPTH) {
> > - struct dp_packet *tnl_pkt[NETDEV_MAX_RX_BATCH];
> > + struct dp_packet *tnl_pkt[NETDEV_MAX_BURST];
> > int err;
> >
> > if (!may_steal) {
> > @@ -3423,7 +3423,7 @@ dp_execute_cb(void *aux_, struct dp_packet **packets,
> int cnt,
> >
> > p = dp_netdev_lookup_port(dp, portno);
> > if (p) {
> > - struct dp_packet *tnl_pkt[NETDEV_MAX_RX_BATCH];
> > + struct dp_packet *tnl_pkt[NETDEV_MAX_BURST];
> > int err;
> >
> > if (!may_steal) {
> > @@ -3485,7 +3485,7 @@ dp_execute_cb(void *aux_, struct dp_packet **packets,
> int cnt,
> >
> > case OVS_ACTION_ATTR_RECIRC:
> > if (*depth < MAX_RECIRC_DEPTH) {
> > - struct dp_packet *recirc_pkts[NETDEV_MAX_RX_BATCH];
> > + struct dp_packet *recirc_pkts[NETDEV_MAX_BURST];
> >
> > if (!may_steal) {
> > dp_netdev_clone_pkt_batch(recirc_pkts, packets, cnt);
> > diff --git a/lib/netdev-dpdk.c b/lib/netdev-dpdk.c
> > index 505ab75..b06f92a 100644
> > --- a/lib/netdev-dpdk.c
> > +++ b/lib/netdev-dpdk.c
> > @@ -99,8 +99,6 @@ BUILD_ASSERT_DECL((MAX_NB_MBUF /
> ROUND_DOWN_POW2(MAX_NB_MBUF/MIN_NB_MBUF))
> > #define TX_HTHRESH 0 /* Default values of TX host threshold reg. */
> > #define TX_WTHRESH 0 /* Default values of TX write-back threshold reg. */
> >
> > -#define MAX_PKT_BURST 32 /* Max burst size for RX/TX */
> > -
> > /* Character device cuse_dev_name. */
> > char *cuse_dev_name = NULL;
> >
> > @@ -862,7 +860,7 @@ netdev_dpdk_vhost_rxq_recv(struct netdev_rxq *rxq_,
> > nb_rx = rte_vhost_dequeue_burst(virtio_dev, qid,
> > vhost_dev->dpdk_mp->mp,
> > (struct rte_mbuf **)packets,
> > - MAX_PKT_BURST);
> > + NETDEV_MAX_BURST);
> > if (!nb_rx) {
> > return EAGAIN;
> > }
> > @@ -889,8 +887,7 @@ netdev_dpdk_rxq_recv(struct netdev_rxq *rxq_, struct
> dp_packet **packets,
> >
> > nb_rx = rte_eth_rx_burst(rx->port_id, rxq_->queue_id,
> > (struct rte_mbuf **) packets,
> > - MIN((int) NETDEV_MAX_RX_BATCH,
> > - (int) MAX_PKT_BURST));
> > + NETDEV_MAX_BURST);
> > if (!nb_rx) {
> > return EAGAIN;
> > }
> > diff --git a/lib/netdev.h b/lib/netdev.h
> > index 71c0af1..9d412ee 100644
> > --- a/lib/netdev.h
> > +++ b/lib/netdev.h
> > @@ -338,7 +338,7 @@ typedef void netdev_dump_queue_stats_cb(unsigned int
> queue_id,
> > int netdev_dump_queue_stats(const struct netdev *,
> > netdev_dump_queue_stats_cb *, void *aux);
> >
> > -enum { NETDEV_MAX_RX_BATCH = 256 }; /* Maximum number packets in
> rx_recv() batch. */
> > +enum { NETDEV_MAX_BURST = 32 }; /* Maximum number packets in a batch. */
> > extern struct seq *tnl_conf_seq;
> >
> > #ifdef __cplusplus
> > --
> > 1.9.1
> >
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