Re: [dpdk-dev] [PATCH 2/2] net/sfc: free mbufs in bulks on simple EF10 Tx datapath reap

[Andrew Rybchenko <arybchenko@solarflare.com>]

On 09/12/2017 09:28 PM, Ferruh Yigit wrote:
> On 9/8/2017 3:15 PM, Andrew Rybchenko wrote:
>> From: Ivan Malov <ivan.malov@oktetlabs.ru>
>>
>> Signed-off-by: Ivan Malov <ivan.malov@oktetlabs.ru>
>> Signed-off-by: Andrew Rybchenko <arybchenko@solarflare.com>
>> ---
>>   doc/guides/nics/sfc_efx.rst   |  4 +++-
>>   drivers/net/sfc/sfc_dp_tx.h   |  2 ++
>>   drivers/net/sfc/sfc_ef10_tx.c | 15 ++++++++++++++-
>>   drivers/net/sfc/sfc_ethdev.c  |  6 ++++++
>>   drivers/net/sfc/sfc_tx.c      | 17 +++++++++++++++++
>>   5 files changed, 42 insertions(+), 2 deletions(-)
>>
>> diff --git a/doc/guides/nics/sfc_efx.rst b/doc/guides/nics/sfc_efx.rst
>> index 973a4a0..028b980 100644
>> --- a/doc/guides/nics/sfc_efx.rst
>> +++ b/doc/guides/nics/sfc_efx.rst
>> @@ -245,12 +245,14 @@ boolean parameters value.
>>     features available and required by the datapath implementation.
>>     **efx** chooses libefx-based datapath which supports VLAN insertion
>>     (full-feature firmware variant only), TSO and multi-segment mbufs.
>> +  Mbuf segments may come from different mempools, and mbuf reference
>> +  counters are treated responsibly.
> This is also the case for ef10 native, right? Does it make sense to
> document it in below too?

Thanks, will add.

>>     **ef10** chooses EF10 (SFN7xxx, SFN8xxx) native datapath which is
>>     more efficient than libefx-based but has no VLAN insertion and TSO
>>     support yet.
>>     **ef10_simple** chooses EF10 (SFN7xxx, SFN8xxx) native datapath which
>>     is even more faster then **ef10** but does not support multi-segment
>> -  mbufs.
>> +  mbufs, disallows multiple mempools and neglects mbuf reference counters.
>>   
>>   - ``perf_profile`` [auto|throughput|low-latency] (default **throughput**)
>>   
> <...>
>
>> --- a/drivers/net/sfc/sfc_ef10_tx.c
>> +++ b/drivers/net/sfc/sfc_ef10_tx.c
>> @@ -401,14 +401,25 @@ struct sfc_ef10_txq {
>>   	pending += sfc_ef10_tx_process_events(txq);
>>   
>>   	if (pending != completed) {
>> +		struct rte_mbuf *bulk[SFC_TX_REAP_BULK_SIZE];
>> +		unsigned int nb = 0;
>> +
>>   		do {
>>   			struct sfc_ef10_tx_sw_desc *txd;
>>   
>>   			txd = &txq->sw_ring[completed & ptr_mask];
>>   
>> -			rte_pktmbuf_free_seg(txd->mbuf);
>> +			if (nb == RTE_DIM(bulk)) {
>> +				rte_mempool_put_bulk(bulk[0]->pool,
>> +						     (void *)bulk, nb);
> same warning here, again false positive I think:
> error #3656: variable "bulk" may be used before its value is set

I think this one is false positive as well.

> The patch to ignore the warning will take care of this one too.
>
>> +				nb = 0;
>> +			}
>> +
>> +			bulk[nb++] = txd->mbuf;
>>   		} while (++completed != pending);
>>   
>> +		rte_mempool_put_bulk(bulk[0]->pool, (void *)bulk, nb);
>> +
>>   		txq->completed = completed;
>>   	}
> <...>
>