From: Srivats P <pstavirs@gmail.com>
To: Xdp <xdp-newbies@vger.kernel.org>
Subject: Re: Jumbo frames with Huge pages
Date: Mon, 21 Mar 2022 22:02:06 +0530 [thread overview]
Message-ID: <CANzUK58uaaH=NA-enNahqgWadOson5pCdGYErGgBQQTudpyFUw@mail.gmail.com> (raw)
In-Reply-To: <CANzUK5919hyHSJf63nWJ2wefG57AKAB7W=D0AkUFKdP9s2BH+w@mail.gmail.com>
> XDP does not allow jumbo frames due to the requirement of frameSize < pageSize.
>
> I'm also aware of the ongoing work related to scatter-gather
> (multi-buffers) to support jumbo frames with XDP.
>
> I'm wondering if jumbo frames can be more simply supported by using
> AF_XDP with huge pages (instead of multi-buffers)? If so, are jumbo
> frames supported in both Rx and Tx directions? I assume this support
> is likely driver specific?
I understand the multi-buffer requirement for the general eBPF/XDP
case to support jumbo frames.
However, for AF_XDP if the UMEM is composed of Huge pages with frame
size set to 8K or 16K and unaligned chunk flag enabled, the AF_XDP
rings (RX/TX) and the NIC rings (RX/TX) should all have buffer sizes
big enough for jumbo frames and direct access should work because it's
all contiguous memory. I don't see a need for multi-buffers for the
AF_XDP use case.
What am I missing?
* Is this use case a snowflake?
* Are there limitations in the ethernet drivers wrt to huge pages or
frame size limits?
Srivats
prev parent reply other threads:[~2022-03-21 16:33 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-03-17 13:13 Jumbo frames with Huge pages Srivats P
2022-03-21 16:32 ` Srivats P [this message]
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