[PATCH v3 05/33] net/ena: fix fast mbuf free

[Ferruh Yigit]

On 3/10/2024 2:58 PM, Brandes, Shai wrote:
> 
> 
>> -----Original Message-----
>> From: Ferruh Yigit <ferruh.yigit at amd.com>
>> Sent: Friday, March 8, 2024 7:23 PM
>> To: Brandes, Shai <shaibran at amazon.com>
>> Cc: dev at dpdk.org; stable at dpdk.org
>> Subject: RE: [EXTERNAL] [PATCH v3 05/33] net/ena: fix fast mbuf free
>>
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>>
>> On 3/6/2024 12:24 PM, shaibran at amazon.com wrote:
>>> From: Shai Brandes <shaibran at amazon.com>
>>>
>>> In case the application enables fast mbuf release optimization, the
>>> driver releases 256 TX mbufs in bulk upon reaching the TX free
>>> threshold.
>>> The existing implementation utilizes rte_mempool_put_bulk for bulk
>>> freeing TXs, which exclusively supports direct mbufs.
>>> In case the application transmits indirect bufs, the driver must also
>>> decrement the mbuf reference count and unlink the mbuf segment.
>>> For such case, the driver should employ rte_pktmbuf_free_bulk.
>>>
>>
>> Ack.
>>
>> I wonder if you observe any performance impact from this change, just for
>> reference if we encounter similar decision in the future.
> [Brandes, Shai] we did not see performance impact in our testing. 
> It was discovered by a new latency application we crafted that uses the bulk free option, which transmitted one by one packets copied from a common buffer, but showed that there are missing packets.
> 

ack.