* RoCE v2 packet size
@ 2020-03-18 22:57 Dimitris Dimitropoulos
2020-03-19 1:54 ` Zhu Yanjun
2020-03-19 6:55 ` Leon Romanovsky
0 siblings, 2 replies; 4+ messages in thread
From: Dimitris Dimitropoulos @ 2020-03-18 22:57 UTC (permalink / raw)
To: linux-rdma
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 ?
Thank you.
Dimitris
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: RoCE v2 packet size
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
1 sibling, 0 replies; 4+ messages in thread
From: Zhu Yanjun @ 2020-03-19 1:54 UTC (permalink / raw)
To: Dimitris Dimitropoulos, linux-rdma
Please refer to SoftRoCE.
On 3/19/2020 6:57 AM, 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 ?
>
> Thank you.
>
> Dimitris
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: RoCE v2 packet size
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
2020-03-19 16:46 ` Dimitris Dimitropoulos
1 sibling, 1 reply; 4+ messages in thread
From: Leon Romanovsky @ 2020-03-19 6:55 UTC (permalink / raw)
To: Dimitris Dimitropoulos; +Cc: linux-rdma
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
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: RoCE v2 packet size
2020-03-19 6:55 ` Leon Romanovsky
@ 2020-03-19 16:46 ` Dimitris Dimitropoulos
0 siblings, 0 replies; 4+ messages in thread
From: Dimitris Dimitropoulos @ 2020-03-19 16:46 UTC (permalink / raw)
To: Leon Romanovsky; +Cc: linux-rdma
Most helpful. Thank you.
Dimitris
On Wed, Mar 18, 2020 at 11:55 PM Leon Romanovsky <leon@kernel.org> wrote:
>
> 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
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2020-03-19 16:47 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz follow: Atom feed
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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
2020-03-19 16:46 ` Dimitris Dimitropoulos
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