rte_pktmbuf_alloc() out of rte_mbufs

rte_pktmbuf_alloc() out of rte_mbufs

[amit sehas]

I am frequently running into out of mbufs when allocating packets. When this happens is there a way to dump counts of which buffers are where so we know what is going on?

I know that each rte_mbuf pool also has per cpu core cache to speed up alloc/free, and some of the buffers will end up there and if one were to never utilize a particular core for a particular mpool perhaps those mbufs are lost ... that is my rough guess ...

How do you debug out of mbufs issue?

regards

Re: rte_pktmbuf_alloc() out of rte_mbufs

[Stephen Hemminger]

On Fri, 22 Nov 2024 02:38:55 +0000 (UTC)
amit sehas <cun23@yahoo.com> wrote:

> I am frequently running into out of mbufs when allocating packets. When this happens is there a way to dump counts of which buffers are where so we know what is going on?
> 
> I know that each rte_mbuf pool also has per cpu core cache to speed up alloc/free, and some of the buffers will end up there and if one were to never utilize a particular core for a particular mpool perhaps those mbufs are lost ... that is my rough guess ...
> 
> How do you debug out of mbufs issue?
> 
> regards

The function rte_mempool_dump() will tell you some information about the status of a particular mempool.
If you enable mempool statistics you can get more info.

The best way to size a memory pool is to account for all the possible places mbuf's can be waiting.
Something like:
   Num Port * Num RxQ * Num RxD + Num Port * Num TxQ * Num TxD + Num Lcores * Burst Size + Num Lcores * Cache size

Often running out of mbufs is because of failure to free an recveived mbuf, or a buggy driver.