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From: Andriy Berestovskyy <aber@semihalf.com>
Date: Wed, 20 Apr 2016 11:35:18 +0200
Message-ID: <CAOysbxosz8vLq682U0q7fmeQqkVHzpuS-reUpBS+XycnBiRFag@mail.gmail.com>
To: Jay Rolette <rolette@infinite.io>
Cc: DPDK <dev@dpdk.org>
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Subject: Re: [dpdk-dev] Couple of PMD questions
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Hi Jay,

On Tue, Apr 19, 2016 at 10:16 PM, Jay Rolette <rolette@infinite.io> wrote:
> Should the driver error out in that case instead of only "sort of" working?

+1, we hit the same issue. Error or log message would help.

> If I support a max frame size of 9216 bytes (exactly a 1K multiple to make
> the NIC happy), then max_rx_pkt_len is going to be 9216 and data_room_size
> will be 9216 + RTE_PKTMBUF_HEADROOM.

Try to set max_rx_pkt_len <= 9K - 8 and mempool element size to 9K +
headroom + size of structures.

> Is that check correct?

Datasheet says:
The MFS does not include the 4 bytes of the VLAN header. Packets with
VLAN header can be as large as MFS + 4. When double VLAN is enabled,
the device adds 8 to the MFS for any packets.


Regards,
Andriy