Re: [PATCH v8] app/testpmd : fix packets not getting flushed in heavy-weight mode API

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

On 2/16/2024 1:56 PM, Ferruh Yigit wrote:
> On 2/16/2024 3:47 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.
>>
>> Fixes: b7091f1dcfbc ("app/testpmd: enable the heavyweight mode TCP/IPv4 GRO")
>> Cc: hujiayu.hu@foxmail.com
>>
>> 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
>>
>> v7:
>>     Address review comments
>>
>> v8:
>>     Fix spell check warnings
>>
>>  app/test-pmd/csumonly.c | 22 ++++++++++++++++++----
>>  1 file changed, 18 insertions(+), 4 deletions(-)
>>
>> diff --git a/app/test-pmd/csumonly.c b/app/test-pmd/csumonly.c
>> index c103e54111..a922160f6d 100644
>> --- a/app/test-pmd/csumonly.c
>> +++ b/app/test-pmd/csumonly.c
>> @@ -863,16 +863,29 @@ 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);
>> -	if (unlikely(nb_rx == 0))
>> +	if (unlikely(nb_rx == 0)) {
>> +#ifndef RTE_LIB_GRO
>>  		return false;
>> +#else
>> +		gro_enable = gro_ports[fs->rx_port].enable;
>> +		/*
>> +		 * Make sure that in case of Heavyweight mode GRO the packets in
>> +		 * GRO cache should be flushed as the timer could have expired.
>> +		 *
>> +		 * The order of conditions should be the same as gro_ctx is valid
>> +		 * only when gro_flush_cycles is not the GRO_DEFAULT_FLUSH_CYCLES which
>> +		 * indicates light weight mode GRO
>> +		 */
>>
> 
> Updated comment as below to make it terse, what do you think:
>  /*
>  * Check if packets need to be flushed in the GRO context
>  * due to a timeout.
>  *
>  * Continue only in GRO heavyweight mode and if there are
>  * packets in the GRO context.
>  */
> 
> 
>> +		if (!gro_enable || (gro_flush_cycles == GRO_DEFAULT_FLUSH_CYCLES) ||
>> +			(rte_gro_get_pkt_count(current_fwd_lcore()->gro_ctx) == 0))
>> +			return false;
>> +#endif
>> +	}
>>
> 
> Another issue but also related to your patch, if there is no packet to
> Tx after GRO block, should we add another zero packet check:
> if (unlikely(nb_rx == 0))
> 	return false;
> 
> To prevent executing GSO and Tx path code with zero packet, do you think
> does this make sense?
> 
> 

Patch looks good to me, with above comment update, but I am worried
about side impacts of this patch that we might be missing, that is why I
would like it to be in -rc1, so that it can be tested better. Hence,


Reviewed-by: Ferruh Yigit <ferruh.yigit@amd.com>

Applied to dpdk-next-net/main, thanks.
(Updated comment as suggested above while merging.)


Lets continue to discuss return on "nb_rx == 0" case after GRO block,
incremental to this patch.