Re: [PATCH 6/6] app/testpmd: factorize fwd engine Tx

["Singh, Aman Deep" <aman.deep.singh@intel.com>]

On 2/14/2023 11:47 PM, Ferruh Yigit wrote:
> On 2/14/2023 11:03 AM, Singh, Aman Deep wrote:
>> On 1/24/2023 4:17 PM, David Marchand wrote:
>>> Reduce code duplication by introducing a helper that takes care of
>>> transmitting, retrying if enabled and incrementing tx counter.
>>>
>>> Signed-off-by: David Marchand <david.marchand@redhat.com>
> <...>
>
>>> diff --git a/app/test-pmd/txonly.c b/app/test-pmd/txonly.c
>>> index b80ab6f5df..7144b3d5eb 100644
>>> --- a/app/test-pmd/txonly.c
>>> +++ b/app/test-pmd/txonly.c
>>> @@ -331,10 +331,9 @@ pkt_burst_transmit(struct fwd_stream *fs)
>>>        struct rte_mbuf *pkt;
>>>        struct rte_mempool *mbp;
>>>        struct rte_ether_hdr eth_hdr;
>>> -    uint16_t nb_tx;
>>> +    uint16_t nb_dropped;
>>>        uint16_t nb_pkt;
>>>        uint16_t vlan_tci, vlan_tci_outer;
>>> -    uint32_t retry;
>>>        uint64_t ol_flags = 0;
>>>        uint64_t tx_offloads;
>>>    @@ -391,34 +390,18 @@ pkt_burst_transmit(struct fwd_stream *fs)
>>>        if (nb_pkt == 0)
>>>            return false;
>>>    -    nb_tx = rte_eth_tx_burst(fs->tx_port, fs->tx_queue, pkts_burst,
>>> nb_pkt);
>>> -
>>> -    /*
>>> -     * Retry if necessary
>>> -     */
>>> -    if (unlikely(nb_tx < nb_pkt) && fs->retry_enabled) {
>>> -        retry = 0;
>>> -        while (nb_tx < nb_pkt && retry++ < burst_tx_retry_num) {
>>> -            rte_delay_us(burst_tx_delay_time);
>>> -            nb_tx += rte_eth_tx_burst(fs->tx_port, fs->tx_queue,
>>> -                    &pkts_burst[nb_tx], nb_pkt - nb_tx);
>>> -        }
>>> -    }
>>> -    fs->tx_packets += nb_tx;
>>> +    nb_dropped = common_fwd_stream_transmit(fs, pkts_burst, nb_pkt);
>>>          if (txonly_multi_flow)
>>> -        RTE_PER_LCORE(_ip_var) -= nb_pkt - nb_tx;
>>> +        RTE_PER_LCORE(_ip_var) -= nb_dropped;
>>>    -    inc_tx_burst_stats(fs, nb_tx);
>>> -    if (unlikely(nb_tx < nb_pkt)) {
>>> +    if (unlikely(nb_dropped > 0)) {
>>>            if (verbose_level > 0 && fs->fwd_dropped == 0)
>>>                printf("port %d tx_queue %d - drop "
>>> -                   "(nb_pkt:%u - nb_tx:%u)=%u packets\n",
>>> -                   fs->tx_port, fs->tx_queue,
>>> -                   (unsigned) nb_pkt, (unsigned) nb_tx,
>>> -                   (unsigned) (nb_pkt - nb_tx));
>>> -        fs->fwd_dropped += (nb_pkt - nb_tx);
>>> -        rte_pktmbuf_free_bulk(&pkts_burst[nb_tx], nb_pkt - nb_tx);
>>> +                "(nb_pkt:%"PRIu16" - nb_tx:%"PRIu16")="
>>> +                "%"PRIu16" packets\n",
>>> +                fs->tx_port, fs->tx_queue, nb_pkt,
>>> +                nb_pkt - nb_dropped, nb_dropped);
>> Build error reported in this file here-
>> ../app/test-pmd/txonly.c:404:5: error: format specifies type 'unsigned
>> short' but the argument has type 'int' [-Werror,-Wformat]
>>
> both 'nb_pkt' & 'nb_dropped' are 'uint16_t' (unsigned short), I wonder
> which argument is causing this warning?

I think, subtraction of two unsigned numbers promotes the result to int.
As 'nb_pkt > nb_dropped', we may explicitly typecast it-
'(unsigned)(nb_pkt - nb_dropped)'

>
>