From: Jakub Kicinski <kuba@kernel.org>
To: Saeed Mahameed <saeed@kernel.org>
Cc: "David S. Miller" <davem@davemloft.net>,
Paolo Abeni <pabeni@redhat.com>,
Eric Dumazet <edumazet@google.com>,
Saeed Mahameed <saeedm@nvidia.com>,
netdev@vger.kernel.org, Tariq Toukan <tariqt@nvidia.com>,
Shay Drory <shayd@nvidia.com>, Moshe Shemesh <moshe@nvidia.com>
Subject: Re: [PATCH net-next] net/mlx5: Introduce SF direction
Date: Fri, 19 May 2023 21:41:01 -0700 [thread overview]
Message-ID: <20230519214101.2452af83@kernel.org> (raw)
In-Reply-To: <20230519183044.19065-1-saeed@kernel.org>
On Fri, 19 May 2023 11:30:44 -0700 Saeed Mahameed wrote:
> Whenever multiple Virtual Network functions (VNFs) are used by Service
> Function Chaining (SFC), each packet is passing through all the VNFs,
> and each VNF is performing hairpin in order to pass the packet to the
> next function in the chain.
>
> In case one mlx5 NIC is servicing multiple VNFs of the SFC, mlx5 need
> user input in order to optimize this hairpin to a simple forward rule.
>
> The optimization is performed by binding two PCI SFs to each VNF, as
> can be seen bellow:
>
> ----------- -----------
> | VNF1 | | VNF2 |
> ----------- -----------
> | | | |
> (Net) SF1| |SF2 (Net) SF3| |SF4
> | | | |
> -------------------------------
> | / \________________/ \ |
> uplink---|/ \|----host
> | NIC(SFC) |
> | |
> -------------------------------
>
> Define SF1 and SF3 as SFs with network direction tell the driver to
> configure the E-switch in a way that the packet arriving from SF1 will
> do forward to SF2 instead of hairpin.
>
> This marking is done via sfnum command line argument, where bit 16
> marks the SF as facing the Network, and bit 17 marks the SF as
> facing the Host.
What does it mean that an SF is "facing" the network?
Why can't the device automatically "optimize" the hairpin?
Or SF1 / SF2 will be uni-directional after this patch?
--
pw-bot: cr
next prev parent reply other threads:[~2023-05-20 4:41 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-05-19 18:30 [PATCH net-next] net/mlx5: Introduce SF direction Saeed Mahameed
2023-05-20 4:41 ` Jakub Kicinski [this message]
2023-05-22 12:47 ` Shay Drory
2023-05-22 21:15 ` Jakub Kicinski
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