From: Jakub Kicinski <kuba@kernel.org>
To: Amit Cohen <amcohen@nvidia.com>
Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>,
Petr Machata <petrm@nvidia.com>,
"David S. Miller" <davem@davemloft.net>,
Eric Dumazet <edumazet@google.com>,
Paolo Abeni <pabeni@redhat.com>,
Andrew Lunn <andrew+netdev@lunn.ch>,
Network Development <netdev@vger.kernel.org>,
Ido Schimmel <idosch@nvidia.com>,
Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Jesper Dangaard Brouer <hawk@kernel.org>,
John Fastabend <john.fastabend@gmail.com>,
bpf <bpf@vger.kernel.org>, mlxsw <mlxsw@nvidia.com>
Subject: Re: [PATCH net-next 00/12] mlxsw: Preparations for XDP support
Date: Wed, 5 Feb 2025 09:09:58 -0800 [thread overview]
Message-ID: <20250205090958.278ffaff@kernel.org> (raw)
In-Reply-To: <BL1PR12MB5922564282DA2C2C5CA671C1CBF42@BL1PR12MB5922.namprd12.prod.outlook.com>
On Tue, 4 Feb 2025 17:26:43 +0000 Amit Cohen wrote:
> > > You're right, most of packets should be handled by HW, XDP is
> > > mainly useful for telemetry.
> >
> > Why skb path is not enough?
>
> We get better packet rates using XDP, this can be useful to redirect
> packets to a server for analysis for example.
TBH I also feel a little ambivalent about adding advanced software
features to mlxsw. You have a dummy device off which you hang the NAPIs,
the page pools, and now the RXQ objects. That already works poorly with
our APIs. How are you going to handle the XDP side? Program per port,
I hope? But the basic fact remains that only fallback traffic goes thru
the XDP program which is not the normal Linux model, routing is after
XDP.
On one hand it'd be great if upstream switch drivers could benefit from
the advanced features. On the other the HW is clearly not capable of
delivering in line with how NICs work, so we're signing up for a stream
of corner cases, bugs and incompatibility. Dunno.
next prev parent reply other threads:[~2025-02-05 17:09 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-02-04 11:04 [PATCH net-next 00/12] mlxsw: Preparations for XDP support Petr Machata
2025-02-04 11:04 ` [PATCH net-next 01/12] mlxsw: core: Remove debug prints Petr Machata
2025-02-04 11:04 ` [PATCH net-next 02/12] mlxsw: Check Rx local port in PCI code Petr Machata
2025-02-04 11:04 ` [PATCH net-next 03/12] mlxsw: Add struct mlxsw_pci_rx_pkt_info Petr Machata
2025-02-04 11:04 ` [PATCH net-next 04/12] mlxsw: pci: Use mlxsw_pci_rx_pkt_info Petr Machata
2025-02-04 11:05 ` [PATCH net-next 05/12] mlxsw: pci: Add a separate function for syncing buffers for CPU Petr Machata
2025-02-04 11:05 ` [PATCH net-next 06/12] mlxsw: pci: Store maximum number of ports Petr Machata
2025-02-04 11:05 ` [PATCH net-next 07/12] mlxsw: pci: Add PCI ports array Petr Machata
2025-02-04 11:05 ` [PATCH net-next 08/12] mlxsw: Add APIs to init/fini PCI port Petr Machata
2025-02-04 11:05 ` [PATCH net-next 09/12] mlxsw: pci: Initialize XDP Rx queue info per RDQ Petr Machata
2025-02-04 11:05 ` [PATCH net-next 10/12] mlxsw: spectrum: Initialize PCI port with the relevant netdevice Petr Machata
2025-02-04 11:05 ` [PATCH net-next 11/12] mlxsw: Set some SKB fields in bus driver Petr Machata
2025-02-04 11:05 ` [PATCH net-next 12/12] mlxsw: Validate local port from CQE in PCI code Petr Machata
2025-02-04 15:56 ` [PATCH net-next 00/12] mlxsw: Preparations for XDP support Alexei Starovoitov
2025-02-04 15:59 ` Amit Cohen
2025-02-04 16:02 ` Alexei Starovoitov
2025-02-04 17:26 ` Amit Cohen
2025-02-05 17:09 ` Jakub Kicinski [this message]
2025-02-15 14:02 ` Simon Horman
2025-02-15 16:10 ` Jakub Kicinski
2025-02-16 9:26 ` Simon Horman
2025-02-17 9:35 ` Ido Schimmel
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