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From: Heng Qi <hengqi@linux.alibaba.com>
To: Jason Wang <jasowang@redhat.com>
Cc: netdev@vger.kernel.org,
	virtualization@lists.linux-foundation.org,
	"Michael S . Tsirkin" <mst@redhat.com>,
	"David S . Miller" <davem@davemloft.net>,
	Eric Dumazet <edumazet@google.com>,
	Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
	Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Jesper Dangaard Brouer <hawk@kernel.org>,
	John Fastabend <john.fastabend@gmail.com>,
	Xuan Zhuo <xuanzhuo@linux.alibaba.com>,
	Gavin Li <gavinl@nvidia.com>
Subject: Re: [PATCH net 5/6] virtio-net: fix the vq coalescing setting for vq resize
Date: Fri, 22 Sep 2023 13:02:42 +0800	[thread overview]
Message-ID: <c95274cd-d119-402b-baf1-0c500472c9fb@linux.alibaba.com> (raw)
In-Reply-To: <CACGkMEuJjxAmr6WC9ETYAw2K9dp0AUoD6LSZCduQyUQ9y7oM3Q@mail.gmail.com>



在 2023/9/22 下午12:29, Jason Wang 写道:
> On Tue, Sep 19, 2023 at 3:49 PM Heng Qi <hengqi@linux.alibaba.com> wrote:
>> According to the definition of virtqueue coalescing spec[1]:
>>
>>    Upon disabling and re-enabling a transmit virtqueue, the device MUST set
>>    the coalescing parameters of the virtqueue to those configured through the
>>    VIRTIO_NET_CTRL_NOTF_COAL_TX_SET command, or, if the driver did not set
>>    any TX coalescing parameters, to 0.
>>
>>    Upon disabling and re-enabling a receive virtqueue, the device MUST set
>>    the coalescing parameters of the virtqueue to those configured through the
>>    VIRTIO_NET_CTRL_NOTF_COAL_RX_SET command, or, if the driver did not set
>>    any RX coalescing parameters, to 0.
>>
>> We need to add this setting for vq resize (ethtool -G) where vq_reset happens.
>>
>> [1] https://lists.oasis-open.org/archives/virtio-dev/202303/msg00415.html
>>
>> Fixes: 394bd87764b6 ("virtio_net: support per queue interrupt coalesce command")
> I'm not sure this is a real fix as spec allows it to go zero?

The spec says that if the user has configured interrupt coalescing 
parameters,
parameters need to be restored after vq_reset, otherwise set to 0.
vi->intr_coal_tx and vi->intr_coal_rx always save the newest global 
parameters,
regardless of whether the command is sent or not. So I think we need 
this patch
it complies with the specification requirements.

Thanks!

>
> Thanks


  reply	other threads:[~2023-09-22  5:02 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-09-19  7:49 [PATCH net 0/6] virtio-net: Fix and update interrupt moderation Heng Qi
2023-09-19  7:49 ` [PATCH net 1/6] virtio-net: initially change the value of tx-frames Heng Qi
2023-09-21  7:03   ` Jason Wang
2023-09-19  7:49 ` [PATCH net 2/6] virtio-net: fix mismatch of getting tx-frames Heng Qi
2023-09-22  3:11   ` Jason Wang
2023-09-19  7:49 ` [PATCH net 3/6] virtio-net: consistently save parameters for per-queue Heng Qi
2023-09-22  4:26   ` Jason Wang
2023-09-19  7:49 ` [PATCH net 4/6] virtio-net: fix per queue coalescing parameter setting Heng Qi
2023-09-22  4:27   ` Jason Wang
2023-09-19  7:49 ` [PATCH net 5/6] virtio-net: fix the vq coalescing setting for vq resize Heng Qi
2023-09-22  4:29   ` Jason Wang
2023-09-22  5:02     ` Heng Qi [this message]
2023-09-22  7:32       ` Jason Wang
2023-09-22  7:58         ` Heng Qi
2023-09-25  2:29           ` Jason Wang
2023-09-25  2:47             ` Heng Qi
2023-09-22  9:50         ` Xuan Zhuo
2023-09-25  2:29           ` Jason Wang
2023-09-25  2:45             ` Heng Qi
2023-09-19  7:49 ` [PATCH net 6/6] virtio-net: a tiny comment update Heng Qi
2023-09-22  4:30   ` Jason Wang

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