Re: [PATCH net-next v2 6/6] tsnep: Add XDP socket zero-copy TX support

[Gerhard Engleder <gerhard@xxxxxxxxxxxxxxxxxxxxx>]

On 18.04.23 10:27, Paolo Abeni wrote:
> On Sat, 2023-04-15 at 16:42 +0200, Gerhard Engleder wrote:
> > Send and complete XSK pool frames within TX NAPI context. NAPI context
> > is triggered by ndo_xsk_wakeup.
> >
> > Test results with A53 1.2GHz:
> >
> > xdpsock txonly copy mode:
> >                     pps            pkts           1.00
> > tx                 284,409        11,398,144
> > Two CPUs with 100% and 10% utilization.
> >
> > xdpsock txonly zero-copy mode:
> >                     pps            pkts           1.00
> > tx                 511,929        5,890,368
> > Two CPUs with 100% and 1% utilization.
> >
> > Packet rate increases and CPU utilization is reduced.
> >
> > Signed-off-by: Gerhard Engleder <gerhard@xxxxxxxxxxxxxxxxxxxxx>
> > ---
> >   drivers/net/ethernet/engleder/tsnep.h      |   2 +
> >   drivers/net/ethernet/engleder/tsnep_main.c | 131 +++++++++++++++++++--
> >   2 files changed, 123 insertions(+), 10 deletions(-)
> >
> > diff --git a/drivers/net/ethernet/engleder/tsnep.h b/drivers/net/ethernet/engleder/tsnep.h
> > index d0bea605a1d1..11b29f56aaf9 100644
> > --- a/drivers/net/ethernet/engleder/tsnep.h
> > +++ b/drivers/net/ethernet/engleder/tsnep.h
> > @@ -70,6 +70,7 @@ struct tsnep_tx_entry {
> >   	union {
> >   		struct sk_buff *skb;
> >   		struct xdp_frame *xdpf;
> > +		bool zc;
> >   	};
> >   	size_t len;
> >   	DEFINE_DMA_UNMAP_ADDR(dma);
> > @@ -88,6 +89,7 @@ struct tsnep_tx {
> >   	int read;
> >   	u32 owner_counter;
> >   	int increment_owner_counter;
> > +	struct xsk_buff_pool *xsk_pool;
> >   
> >   	u32 packets;
> >   	u32 bytes;
> > diff --git a/drivers/net/ethernet/engleder/tsnep_main.c b/drivers/net/ethernet/engleder/tsnep_main.c
> > index 13e5d4438082..de51d0cc8935 100644
> > --- a/drivers/net/ethernet/engleder/tsnep_main.c
> > +++ b/drivers/net/ethernet/engleder/tsnep_main.c
> > @@ -54,6 +54,8 @@
> >   #define TSNEP_TX_TYPE_SKB_FRAG	BIT(1)
> >   #define TSNEP_TX_TYPE_XDP_TX	BIT(2)
> >   #define TSNEP_TX_TYPE_XDP_NDO	BIT(3)
> > +#define TSNEP_TX_TYPE_XDP	(TSNEP_TX_TYPE_XDP_TX | TSNEP_TX_TYPE_XDP_NDO)
> > +#define TSNEP_TX_TYPE_XSK	BIT(4)
> >   
> >   #define TSNEP_XDP_TX		BIT(0)
> >   #define TSNEP_XDP_REDIRECT	BIT(1)
> > @@ -322,13 +324,51 @@ static void tsnep_tx_init(struct tsnep_tx *tx)
> >   	tx->increment_owner_counter = TSNEP_RING_SIZE - 1;
> >   }
> >   
> > +static void tsnep_tx_enable(struct tsnep_tx *tx)
> > +{
> > +	struct netdev_queue *nq;
> > +
> > +	nq = netdev_get_tx_queue(tx->adapter->netdev, tx->queue_index);
> > +
> > +	local_bh_disable();
> > +	__netif_tx_lock(nq, smp_processor_id());
>
> The above 2 statements could be replaced with:
>
> 	__netif_tx_lock_bh()
>
> > +	netif_tx_wake_queue(nq);
> > +	__netif_tx_unlock(nq);
> > +	local_bh_enable();
>
> __netif_tx_unlock_bh()
>
> > +}
> > +
> > +static void tsnep_tx_disable(struct tsnep_tx *tx, struct napi_struct *napi)
> > +{
> > +	struct netdev_queue *nq;
> > +	u32 val;
> > +
> > +	nq = netdev_get_tx_queue(tx->adapter->netdev, tx->queue_index);
> > +
> > +	local_bh_disable();
> > +	__netif_tx_lock(nq, smp_processor_id());
>
> Same here.

Will be done.

Thank you!

Gerhard