netdev - Re: Question about TPA/HDS feature of bnxt

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Message-ID: <CAMArcTV4nHDpwKTH0JxcLB2tU23gTDtvFp5wNWjJNdw8+ZFGqw@mail.gmail.com>
Date: Wed, 14 Aug 2024 16:27:10 +0900
From: Taehee Yoo <ap420073@...il.com>
To: Jakub Kicinski <kuba@...nel.org>
Cc: Michael Chan <michael.chan@...adcom.com>, David Wei <dw@...idwei.uk>, 
	Somnath Kotur <somnath.kotur@...adcom.com>, Mina Almasry <almasrymina@...gle.com>, 
	Netdev <netdev@...r.kernel.org>
Subject: Re: Question about TPA/HDS feature of bnxt_en

On Wed, Aug 14, 2024 at 10:17 AM Jakub Kicinski <kuba@...nel.org> wrote:
>

Hi Jakub,

> On Tue, 13 Aug 2024 19:42:51 +0900 Taehee Yoo wrote:
> > Hi,
> > I'm currently testing the device memory TCP feature with the bnxt_en
> > driver because Broadcom NICs support TPA/HDS, which is a mandatory
> > feature for the devmem TCP.
> > But it doesn't work for short-sized packets(under 300?)
> > So, the devmem TCP stops or errors out if it receives non-header-splitted skb.
> >
> > I hope the bnxt_en driver or firmware has options that force TPA to
> > work for short-sized packets.
> > So, Can I get any condition information on TPA?
>
> I don't have any non-public info but look around the driver for
> rx_copy_thresh, it seems to be sent to FW. I wonder if setting
> it to 1 or 0 would work. Especially this:
>
> static int bnxt_hwrm_vnic_set_hds(struct bnxt *bp, struct bnxt_vnic_info *vnic)
> ...
> req->hds_threshold = cpu_to_le16(bp->rx_copy_thresh);

Thank you so much for looking into this!
As you said, I tested setting hds_threshold to 0, it works well.
I think we can implement `ethtool -G eth0 tcp-data-split on` option with this.

Thank you so much again,
Taehee Yoo