From: "Michael S. Tsirkin" <mst@redhat.com>
To: Eli Cohen <elic@nvidia.com>
Cc: eperezma@redhat.com, parav@mellanox.com,
virtualization@lists.linux-foundation.org
Subject: Re: [PATCH v4 1/2] vdpa/mlx5: Make VIRTIO_NET_F_MRG_RXBUF off by default
Date: Tue, 21 Mar 2023 23:32:32 -0400 [thread overview]
Message-ID: <20230321232937-mutt-send-email-mst@kernel.org> (raw)
In-Reply-To: <20230321112809.221432-2-elic@nvidia.com>
On Tue, Mar 21, 2023 at 01:28:08PM +0200, Eli Cohen wrote:
> Following patch adds driver support for VIRTIO_NET_F_MRG_RXBUF.
>
> Current firmware versions show degradation in packet rate when using
> MRG_RXBUF. Users who favor memory saving over packet rate could enable
> this feature but we want to keep it off by default.
>
> One can still enable it when creating the vdpa device using vdpa tool by
> providing features that include it.
>
> For example:
> $ vdpa dev add name vdpa0 mgmtdev pci/0000:86:00.2 device_features 0x300cb982b
>
>
> Acked-by: Jason Wang <jasowang@redhat.com>
> Signed-off-by: Eli Cohen <elic@nvidia.com>
I have a question. Could you guys try with the recent XDP mergeable
buffer rework? Does this address the performance issue you are
observing?
Specifically:
Message-Id: <20230322025701.2955-1-xuanzhuo@linux.alibaba.com>
Message-Id: <20230322030308.16046-1-xuanzhuo@linux.alibaba.com>
I would very much appreciate if you posted perf numbers
in response to that thread - both to help evaluate that
patchset and this one.
Thanks!
> ---
> drivers/vdpa/mlx5/net/mlx5_vnet.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c b/drivers/vdpa/mlx5/net/mlx5_vnet.c
> index 520646ae7fa0..502c482a93ce 100644
> --- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
> +++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c
> @@ -3122,6 +3122,8 @@ static int mlx5_vdpa_dev_add(struct vdpa_mgmt_dev *v_mdev, const char *name,
> return -EINVAL;
> }
> device_features &= add_config->device_features;
> + } else {
> + device_features &= ~BIT_ULL(VIRTIO_NET_F_MRG_RXBUF);
> }
> if (!(device_features & BIT_ULL(VIRTIO_F_VERSION_1) &&
> device_features & BIT_ULL(VIRTIO_F_ACCESS_PLATFORM))) {
> --
> 2.38.1
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next prev parent reply other threads:[~2023-03-22 3:32 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20230321112809.221432-1-elic@nvidia.com>
[not found] ` <20230321112809.221432-2-elic@nvidia.com>
2023-03-21 23:33 ` [PATCH v4 1/2] vdpa/mlx5: Make VIRTIO_NET_F_MRG_RXBUF off by default Si-Wei Liu
2023-03-22 3:32 ` Michael S. Tsirkin [this message]
2023-03-22 3:35 ` Michael S. Tsirkin
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