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From: Leon Romanovsky <leon@kernel.org>
To: Dimitris Dimitropoulos <d.dimitropoulos@imatrex.com>
Cc: linux-rdma@vger.kernel.org
Subject: Re: RoCE v2 packet size
Date: Thu, 19 Mar 2020 08:55:28 +0200	[thread overview]
Message-ID: <20200319065528.GL126814@unreal> (raw)
In-Reply-To: <CAOc41xF2xRfSpZDn-XRA=R+SegMJTPU6GJe6_6q=0j4=a-Bw9w@mail.gmail.com>

On Wed, Mar 18, 2020 at 03:57:33PM -0700, Dimitris Dimitropoulos wrote:
> Hi,
>
> In RoCE v2 there various options for the protocol packet size: 4096,
> 2048, etc. To what does this number refer to exactly. Is it the
> payload that ends up in the QP buffers, or does it include headers
> some of the headers as well ?

If I'm looking on the correct RoCE spec section (A17.3.1.2.3 PAYLOAD LENGTH).
It doesn't include headers but does include ICRC.

The section "5.2.13 PAYLOAD" in the IBTA spec says that:
"C5-8: All packets of an IBA message that contain a payload shall fill the
payload to the full path MTU except the last (or only) packet of the message."

This is why headers aren't included.

Thanks

>
> Thank you.
>
> Dimitris

  parent reply	other threads:[~2020-03-19  6:55 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-18 22:57 RoCE v2 packet size Dimitris Dimitropoulos
2020-03-19  1:54 ` Zhu Yanjun
2020-03-19  6:55 ` Leon Romanovsky [this message]
2020-03-19 16:46   ` Dimitris Dimitropoulos

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