From: Stephen Hemminger <stephen@networkplumber.org>
To: Ferruh Yigit <ferruh.yigit@intel.com>
Cc: Kamaraj P <pkamaraj@gmail.com>, dev <dev@dpdk.org>,
"Burakov, Anatoly" <anatoly.burakov@intel.com>
Subject: Re: [dpdk-dev] DPDK Max Mbuf Allocation
Date: Mon, 13 Sep 2021 08:51:04 -0700 [thread overview]
Message-ID: <20210913085104.064bcc39@hermes.local> (raw)
In-Reply-To: <2a936b73-9935-6cd9-6d05-780d2f28982f@intel.com>
On Mon, 13 Sep 2021 16:43:18 +0100
Ferruh Yigit <ferruh.yigit@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
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
MBUF_PER_Q = 6
and when using jumbo
MBUF_PER_TX = MAX_MTU / MBUF_DATA_SIZE = 2
next prev parent reply other threads:[~2021-09-13 15:51 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-13 4:56 Kamaraj P
2021-09-13 15:43 ` Ferruh Yigit
2021-09-13 15:51 ` Stephen Hemminger [this message]
2021-09-14 2:04 ` Lance Richardson
2021-09-16 5:12 ` Kamaraj P
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