mempool cache change

[fengchengwen]

On 7/15/2026 4:08 AM, Morten Brørup wrote:
> Hi Kishore,
> 
> For your testing purposes, please follow the guidance provided to Wisam Jaddo:
> https://inbox.dpdk.org/dev/98CBD80474FA8B44BF855DF32C47DC35F65964@smartserver.smartshare.dk/

We need to recompile in this case. We should try to avoid recompilation.
I think it is necessary to adjust RTE_MEMPOOL_CACHE_MAX_SIZE to 768 as a
default configuration.

Thanks

> 
> Thank you for testing!
> 
> Venlig hilsen / Kind regards,
> -Morten Brørup
> 
> From: Kishore Padmanabha [mailto:kishore.padmanabha at broadcom.com] 
> Sent: Tuesday, 14 July 2026 18.49
> To: Thomas Monjalon; Morten Brørup
> Cc: dev at dpdk.org
> Subject: mempool cache change
> 
> Hi Thomas,
>  
> The recent change done as part of BUG ID: 1027, with commit id  https://git.dpdk.org/dpdk/commit/?id=f5e1310f16e0909e7e7f71807123644c63b23cba
> Is causing performance drop for the bnxt NIC in 26.07 release.
>  
> The smaller, shallower cache increases the miss rate, causing refills to hit the shared ring more frequently. 
> In the old code, the cache only touched the shared ring when it climbed past 768 instead of 512. That extra 256 elements of headroom allowed significantly more frees to remain local.
>  
> Could we make the change in config/rte_config.h for RTE_MEMPOOL_CACHE_MAX_SIZE to be 768 instead of 512. Since we use –mbcache=512 as argument for the performance tests.
>  
> Thanks,
> Kishore
>  
>