[PATCH 4/5] net/ena: add support for ena-express metrics

[Brandes, Shai]

On Tue, 24 Oct 2023 13:21:27 +0300
<shaibran at amazon.com> wrote:

>>  struct ena_offloads {
>>       uint32_t tx_offloads;
>>       uint32_t rx_offloads;
>> @@ -329,6 +346,7 @@ struct ena_adapter {
>>        */
>>       uint64_t metrics_stats[ENA_MAX_CUSTOMER_METRICS] __rte_cache_aligned;
>>       uint16_t metrics_num;
>> +     struct ena_stats_srd srd_stats __rte_cache_aligned;
>>  };

> If metrics_num was before the metrics_stats[] you would save some space.
Thank you for the review! My reasoning was that the metrics_num should reside in the same cache line as the metrics_stats (metrics_stats can contain up to 6 metrics so its max length is 48B).
In addition, the  struct ena_stats_srd was added in a later patch, so I will run pahole and verify which order of these three fields gives the best results.
BTW, we are starting a cache optimization task now that should address all these issues, this is indeed one of our main structures, so it will definitely get modified later.