Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::3:2 as permitted sender) client-ip=2620:137:e000::3:2;
Message-ID: <0c2efe49-03db-4616-a4e5-26ff0434e323@linux.dev>
Date:   Wed, 29 Nov 2023 23:29:10 +0800
MIME-Version: 1.0
Subject: Re: [PATCH net-next 2/5] virtio_net: Add page_pool support to improve
 performance
From:   Zhu Yanjun <yanjun.zhu@linux.dev>
To:     "Michael S. Tsirkin" <mst@redhat.com>
Cc:     Liang Chen <liangchen.linux@gmail.com>, jasowang@redhat.com,
        virtualization@lists.linux-foundation.org, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org, xuanzhuo@linux.alibaba.com,
        kuba@kernel.org, edumazet@google.com, davem@davemloft.net,
        pabeni@redhat.com, alexander.duyck@gmail.com
References: <20230526054621.18371-1-liangchen.linux@gmail.com>
 <20230526054621.18371-2-liangchen.linux@gmail.com>
 <c745f67e-91e6-4a32-93f2-dc715056eb51@linux.dev>
 <20231129095825-mutt-send-email-mst@kernel.org>
 <b699fbc8-260a-48e9-b6cc-8bfecd09afed@linux.dev>
In-Reply-To: <b699fbc8-260a-48e9-b6cc-8bfecd09afed@linux.dev>
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 8bit
Precedence: bulk


在 2023/11/29 23:22, Zhu Yanjun 写道:
>
> 在 2023/11/29 22:59, Michael S. Tsirkin 写道:
>> On Wed, Nov 29, 2023 at 10:50:57PM +0800, Zhu Yanjun wrote:
>>> 在 2023/5/26 13:46, Liang Chen 写道:
>>
>> what made you respond to a patch from May, now?
>
> I want to apply page_pool to our virtio_net. This virtio_net works on 
> our device.
>
> I want to verify whether page_pool on virtio_net with our device can 
> improve the performance or not.
>
> And I found that ethtool is wrong.
>
> I use virtio_net on our device. I found that page member variable in 
> rq is not used in recv path.
>
> When virtio_net is modprobe, I checked page member variable in rq with 
> kprobe or crash tool.  page member variable in rq is always NULL.
>
> But sg in recv path is used.
>
> So how to use page member variable in rq? If page member variable in 
> rq is always NULL, can we remove it?
>
> BTW, I use ping and iperf tool to make tests with virtio_net. In the 
> tests, page member variable in rq is always NULL.


And I replaced page member variable in rq with page_pool, but the 
statistics of page_pool are always 0.

It is interesting that page_pool member variable in rq is not used in 
ping and iperf tests.

I am not sure what tests can make page member variable not NULL. ^_^

Best Regards,

Zhu Yanjun


>
> It is interesting.
>
> Zhu Yanjun
>
>>