On Mon, Sep 13, 2021 at 11:51 AM Stephen Hemminger <step...@networkplumber.org> wrote: > > On Mon, 13 Sep 2021 16:43:18 +0100 > Ferruh Yigit <ferruh.yi...@intel.com> wrote: > > > On 9/13/2021 5:56 AM, Kamaraj P wrote: > > > Hello All, > > > > > > Would like to understand or if there are any guidelines to allocate the > > > max > > > no of mbuf per NIC ? > > > For example, if i have defined as below: > > > #define RX_RING_SIZE 1024 > > > #define TX_RING_SIZE 1024 > > > > > > The Maximum RX/TX queues can be defined as 8 per NIC, What would be the > > > max > > > no of mbuf can be allocated per NIC ? > > > Please share if there is any guildliness or any limitation to increase the > > > mbuf ? > > > > > > > Hi Kamaraj, > > > > Max number of the queues and max number of the descriptors per queue > > depends to > > HW and changes form HW to HW. > > This information is shared by the PMDs that application needs to take into > > account. For example the descriptor limitations are provided by > > 'rx_desc_lim'/'tx_desc_lim' etc. > > > > After descriptor number is defined, testpmd uses the mbuf count as > > following, > > which can be taken as sample: > > > > nb_mbuf_per_pool = RTE_TEST_RX_DESC_MAX + RTE_TEST_TX_DESC_MAX + > > MAX_PKT_BURST + > > (nb_lcores * mb_mempool_cache); > > > > It is a a little more complicated since some devices (like bnxt) allocate > multiple mbuf's per packet. Something like
+1, and it's worth noting that this makes it difficult to run many sample applications on the bnxt PMD. > > nb_mbuf_per_pool = MAX_RX_QUEUES * (RTE_TEST_RX_DESC_MAX * MBUF_PER_RX + > MBUF_PER_Q) > + MAX_TX_QUEUE * RTE_TEST_TX_DESC_MAX * MBUF_PER_TX > + nb_lcores * MAX_PKT_BURST > + nb_lcores * mb_mempool_cache > + nb_lcores * PKTMBUF_POOL_RESERVED; > > Ended up with > MBUF_PER_RX = 3 For releases up to around 20.11, 3 is the correct value (one mbuf per RX ring entry, two mbufs in each aggregation ring per RX ring entry). Currently the value for MBUF_PER_RX would be 5 (four mbufs in each aggregation ring for each RX ring entry). BTW, a future version will avoid populating aggregation rings with mbufs when LRO or scattered receive are not enabled. > MBUF_PER_Q = 6 Hmm, it's not clear where these would be allocated in the bnxt PMD. It seems to me that MBUF_PER_Q is zero for the bnxt PMD. > and when using jumbo > MBUF_PER_TX = MAX_MTU / MBUF_DATA_SIZE = 2 I don't think this is correct... the bnxt PMD allocates TX descriptor rings with the requested number of descriptors from tx_queue_setup(), this is the maximum number of mbufs that can be present in a TX ring. > > > > >
