Hi Maryam,
On Thu, Feb 6, 2025 at 2:09 AM Maryam Tahhan <mtah...@redhat.com> wrote:
>
>
> On Sat 1 Feb 2025, 10:03 Ariel Otilibili, <ariel.otilib...@6wind.com>
> wrote:
>
>> Both legs of the loop share the same logic: the common parts are about
>> reserving and filling both address and length into the description.
>>
>> This is moved into reserve_and_fill().
>>
>> Bugzilla ID: 1440
>> Suggested-by: Maryam Tahhan <mtah...@redhat.com>
>> Signed-off-by: Ariel Otilibili <ariel.otilib...@6wind.com>
>> ---
>> drivers/net/af_xdp/rte_eth_af_xdp.c | 62 ++++++++++++++++-------------
>> 1 file changed, 34 insertions(+), 28 deletions(-)
>>
>> diff --git a/drivers/net/af_xdp/rte_eth_af_xdp.c
>> b/drivers/net/af_xdp/rte_eth_af_xdp.c
>> index 092bcb73aa0a..840a12dbf508 100644
>> --- a/drivers/net/af_xdp/rte_eth_af_xdp.c
>> +++ b/drivers/net/af_xdp/rte_eth_af_xdp.c
>> @@ -536,6 +536,31 @@ kick_tx(struct pkt_tx_queue *txq, struct
>> xsk_ring_cons *cq)
>> }
>> }
>>
>> +static inline struct xdp_desc *
>> +reserve_and_fill(struct pkt_tx_queue *txq, struct rte_mbuf *mbuf,
>> + struct xsk_umem_info *umem)
>> +{
>> + struct xdp_desc *desc = NULL;
>> + uint32_t *idx_tx = NULL;
>> + uint64_t addr, offset;
>> +
>> + if (!xsk_ring_prod__reserve(&txq->tx, 1, idx_tx))
>> + goto out;
>> +
>> + desc = xsk_ring_prod__tx_desc(&txq->tx, *idx_tx);
>> + desc->len = mbuf->pkt_len;
>> +
>> + addr = (uint64_t)mbuf - (uint64_t)umem->buffer
>> + - umem->mb_pool->header_size;
>> + offset = rte_pktmbuf_mtod(mbuf, uint64_t) - (uint64_t)mbuf
>> + + umem->mb_pool->header_size;
>> + offset = offset << XSK_UNALIGNED_BUF_OFFSET_SHIFT;
>> + desc->addr = addr | offset;
>> +
>> +out:
>> + return desc;
>> +}
>> +
>> #if defined(XDP_UMEM_UNALIGNED_CHUNK_FLAG)
>> static uint16_t
>> af_xdp_tx_zc(void *queue, struct rte_mbuf **bufs, uint16_t nb_pkts)
>> @@ -545,10 +570,8 @@ af_xdp_tx_zc(void *queue, struct rte_mbuf **bufs,
>> uint16_t nb_pkts)
>> struct rte_mbuf *mbuf;
>> unsigned long tx_bytes = 0;
>> int i;
>> - uint32_t idx_tx;
>> uint16_t count = 0;
>> struct xdp_desc *desc;
>> - uint64_t addr, offset;
>> struct xsk_ring_cons *cq = &txq->pair->cq;
>> uint32_t free_thresh = cq->size >> 1;
>>
>> @@ -559,21 +582,12 @@ af_xdp_tx_zc(void *queue, struct rte_mbuf **bufs,
>> uint16_t nb_pkts)
>> mbuf = bufs[i];
>>
>> if (mbuf->pool == umem->mb_pool) {
>> - if (!xsk_ring_prod__reserve(&txq->tx, 1,
>> &idx_tx)) {
>> + if (!(desc = reserve_and_fill(txq, mbuf, umem))) {
>> kick_tx(txq, cq);
>> - if (!xsk_ring_prod__reserve(&txq->tx, 1,
>> - &idx_tx))
>> + if (!(desc = reserve_and_fill(txq, mbuf,
>> umem)))
>> goto out;
>> }
>> - desc = xsk_ring_prod__tx_desc(&txq->tx, idx_tx);
>> - desc->len = mbuf->pkt_len;
>> - addr = (uint64_t)mbuf - (uint64_t)umem->buffer -
>> - umem->mb_pool->header_size;
>> - offset = rte_pktmbuf_mtod(mbuf, uint64_t) -
>> - (uint64_t)mbuf +
>> - umem->mb_pool->header_size;
>> - offset = offset << XSK_UNALIGNED_BUF_OFFSET_SHIFT;
>> - desc->addr = addr | offset;
>> +
>> tx_bytes += desc->len;
>> count++;
>> } else {
>> @@ -584,26 +598,18 @@ af_xdp_tx_zc(void *queue, struct rte_mbuf **bufs,
>> uint16_t nb_pkts)
>> if (local_mbuf == NULL)
>> goto out;
>>
>> - if (!xsk_ring_prod__reserve(&txq->tx, 1,
>> &idx_tx)) {
>> + if (!(desc = reserve_and_fill(txq, local_mbuf,
>> umem))) {
>> rte_pktmbuf_free(local_mbuf);
>> goto out;
>> }
>>
>> - desc = xsk_ring_prod__tx_desc(&txq->tx, idx_tx);
>> - desc->len = mbuf->pkt_len;
>> -
>>
>
> So I think i spotted one issue, you might need override desc->len after
> the call to the reserve_and_fill function so as it's not taken supposed to
> be from local_mbuf here.
>
You are right; I will do that.
>
> - addr = (uint64_t)local_mbuf -
>> (uint64_t)umem->buffer -
>> - umem->mb_pool->header_size;
>> - offset = rte_pktmbuf_mtod(local_mbuf, uint64_t) -
>> - (uint64_t)local_mbuf +
>> - umem->mb_pool->header_size;
>> - pkt = xsk_umem__get_data(umem->buffer, addr +
>> offset);
>> - offset = offset << XSK_UNALIGNED_BUF_OFFSET_SHIFT;
>> - desc->addr = addr | offset;
>> + pkt = xsk_umem__get_data(umem->buffer,
>> + (desc->addr & ~0xFFF)
>> + + (desc->addr & 0xFFF));
>>
>
> Would prefer to move this pkt assignment to reserve_and_fill()
> What if we passed a void **ppkt to reserve_and_fill() then kept the
> original logic just wrapped in a NULL check?
>
It would look neater, indeed.
>
> if (ppkt) {
> *ppkt = xsk_umem__get_data(umem->buffer, addr + offset);
> }
>
>
> Before the offset and desc->addr
> offset = offset << XSK_UNALIGNED_BUF_OFFSET_SHIFT;
> desc->addr = addr | offset;
>
> WDYT?
>
I will; thanks for the proposal.
For me to sum up which changes are needed:
* change desc->len to local_buf
* move pkt initialization into reserve_and_fill
* change idx_tx from uint32_t* to uint32_t (
https://inbox.dpdk.org/dev/CAF1zDgZgJZgWOeG=rajicmgvt24pttb9b0ukwh_rde3ooey...@mail.gmail.com/
)
Thanks again,
Ariel
>
> rte_memcpy(pkt, rte_pktmbuf_mtod(mbuf, void *),
>> - desc->len);
>> - tx_bytes += desc->len;
>> + desc->len);
>> rte_pktmbuf_free(mbuf);
>> + tx_bytes += desc->len;
>> count++;
>> }
>> }
>> --
>> 2.30.2
>>
>>
