Re: [PATCH v6] gro : packets not getting flushed in heavy-weight mode API

[Ferruh Yigit <ferruh.yigit@amd.com>]

On 2/11/2024 4:55 AM, Kumara Parameshwaran wrote:
> In heavy-weight mode GRO which is based on timer, the GRO packets
> will not be flushed in spite of timer expiry if there is no packet
> in the current poll. If timer mode GRO is enabled the
> rte_gro_timeout_flush API should be invoked.
> 

Related to the patch title, 'gro: ' indicates a component for gro
library (lib/gro), but this is a testpmd patch, can you please update it as:
"app/testpmd: <verb> ..."

And can you please add a fixes tag [1], so this patch can be backported.

[1]
https://doc.dpdk.org/guides/contributing/patches.html#commit-messages-body


> Signed-off-by: Kumara Parameshwaran <kumaraparamesh92@gmail.com>
> ---
> v1:
>     Changes to make sure that the GRO flush API is invoked if there are no packets in 
>     current poll and timer expiry.
> 
> v2:
>     Fix code organisation issue
> 
> v3:
>     Fix warnings
> 
> v4:
>     Fix error and warnings
> 
> v5:
>     Fix compilation issue when GRO is not defined
> 
> v6:
>     Address review comments
> 
>  app/test-pmd/csumonly.c | 14 ++++++++++----
>  1 file changed, 10 insertions(+), 4 deletions(-)
> 
> diff --git a/app/test-pmd/csumonly.c b/app/test-pmd/csumonly.c
> index c103e54111..21b45b4ba4 100644
> --- a/app/test-pmd/csumonly.c
> +++ b/app/test-pmd/csumonly.c
> @@ -863,16 +863,22 @@ pkt_burst_checksum_forward(struct fwd_stream *fs)
>  
>  	/* receive a burst of packet */
>  	nb_rx = common_fwd_stream_receive(fs, pkts_burst, nb_pkt_per_burst);
> +#ifndef RTE_LIB_GRO
>  	if (unlikely(nb_rx == 0))
>  		return false;
> -
> +#else
> +	gro_enable = gro_ports[fs->rx_port].enable;
> +	if (unlikely(nb_rx == 0)) {
> +		if (!gro_enable || (gro_flush_cycles == GRO_DEFAULT_FLUSH_CYCLES))
> +			return false;
> +		if ((rte_gro_get_pkt_count(current_fwd_lcore()->gro_ctx) == 0))
> +			return false;
>

Why not "||" this condition to previous if block, instead of adding a
new if?


> +	}
> +#endif
>

Can you please put a comment in the GRO block that explains why these
checks are done and why we may not want to return although 'nb_rx == 0'?


Another option is make the block as below and keep the code below to get
'gro_enable':
```
if (unlikely(nb_rx == 0)) {
#ifndef RTE_LIB_GRO
	return false;
#else
	// Comment explaining what is done here
	gro_enable = gro_ports[fs->rx_port].enable;
	if (...)
		return false;
#endif
}
```

Above sample that keeps the #ifdef in a narrow scope ("nb_rx == 0"
block) looks tidier to me, but both works fine, no strong opinion from
me, what do you think?


>  	rx_bad_ip_csum = 0;
>  	rx_bad_l4_csum = 0;
>  	rx_bad_outer_l4_csum = 0;
>  	rx_bad_outer_ip_csum = 0;
> -#ifdef RTE_LIB_GRO
> -	gro_enable = gro_ports[fs->rx_port].enable;
> -#endif
>  
>  	txp = &ports[fs->tx_port];
>  	tx_offloads = txp->dev_conf.txmode.offloads;