From: Tariq Toukan <ttoukan.linux@gmail.com>
To: Eric Dumazet <edumazet@google.com>,
"David S . Miller" <davem@davemloft.net>,
Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>
Cc: Tariq Toukan <tariqt@nvidia.com>,
Leon Romanovsky <leonro@nvidia.com>,
netdev@vger.kernel.org, eric.dumazet@gmail.com,
Wei Wang <weiwan@google.com>
Subject: Re: [PATCH v2 net-next 2/3] net/mlx4: MLX4_TX_BOUNCE_BUFFER_SIZE depends on MAX_SKB_FRAGS
Date: Wed, 7 Dec 2022 20:53:51 +0200 [thread overview]
Message-ID: <7beeecae-8d6f-d4c2-db43-ddf468469ca0@gmail.com> (raw)
In-Reply-To: <20221207141237.2575012-3-edumazet@google.com>
On 12/7/2022 4:12 PM, Eric Dumazet wrote:
> Google production kernel has increased MAX_SKB_FRAGS to 45
> for BIG-TCP rollout.
>
> Unfortunately mlx4 TX bounce buffer is not big enough whenever
> an skb has up to 45 page fragments.
>
> This can happen often with TCP TX zero copy, as one frag usually
> holds 4096 bytes of payload (order-0 page).
>
> Tested:
> Kernel built with MAX_SKB_FRAGS=45
> ip link set dev eth0 gso_max_size 185000
> netperf -t TCP_SENDFILE
>
> I made sure that "ethtool -G eth0 tx 64" was properly working,
> ring->full_size being set to 15.
>
> Signed-off-by: Eric Dumazet <edumazet@google.com>
> Reported-by: Wei Wang <weiwan@google.com>
> Cc: Tariq Toukan <tariqt@nvidia.com>
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
next prev parent reply other threads:[~2022-12-07 18:53 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-12-07 14:12 [PATCH v2 net-next 0/3] mlx4: better BIG-TCP support Eric Dumazet
2022-12-07 14:12 ` [PATCH v2 net-next 1/3] net/mlx4: rename two constants Eric Dumazet
2022-12-07 18:53 ` Tariq Toukan
2022-12-07 14:12 ` [PATCH v2 net-next 2/3] net/mlx4: MLX4_TX_BOUNCE_BUFFER_SIZE depends on MAX_SKB_FRAGS Eric Dumazet
2022-12-07 18:53 ` Tariq Toukan [this message]
2022-12-07 14:12 ` [PATCH v2 net-next 3/3] net/mlx4: small optimization in mlx4_en_xmit() Eric Dumazet
2022-12-07 18:54 ` Tariq Toukan
2022-12-08 22:30 ` [PATCH v2 net-next 0/3] mlx4: better BIG-TCP support patchwork-bot+netdevbpf
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