From: Jason Wang <jasowang@redhat.com>
To: Qin Chuanyu <qinchuanyu@huawei.com>, davem@davemloft.net
Cc: "Michael S. Tsirkin" <mst@redhat.com>,
Anthony Liguori <anthony@codemonkey.ws>,
KVM list <kvm@vger.kernel.org>,
netdev@vger.kernel.org, Eric Dumazet <eric.dumazet@gmail.com>
Subject: Re: [PATCH] tun: use netif_receive_skb instead of netif_rx_ni
Date: Wed, 12 Feb 2014 15:40:36 +0800 [thread overview]
Message-ID: <52FB2574.4070004@redhat.com> (raw)
In-Reply-To: <52FB18B8.4070401@huawei.com>
On 02/12/2014 02:46 PM, Qin Chuanyu wrote:
> On 2014/2/12 13:28, Jason Wang wrote:
>
>> A question: without NAPI weight, could this starve other net devices?
> tap xmit skb use thread context，the poll func of physical nic driver
> could be called in softirq context without change.
>
> I had test it by binding vhost thread and physic nic interrupt on the
> same vcpu, use netperf xmit udp, test model is VM1-Host1-Host2.
>
> if only VM1 xmit skb, the top show as below :
> Cpu1 :0.0%us, 95.0%sy, 0.0%ni, 0.0%id, 0.0%wa, 0.0%hi, 5.0%si, 0.0%st
>
> then use host2 xmit skb to VM1, the top show as below :
> Cpu1 :0.0%us, 41.0%sy, 0.0%ni, 0.0%id, 0.0%wa, 0.0%hi, 59.0%si, 0.0%st
>
> so I think there is no problem with this change.
Yes, I realize it was ok after Eric's comment.
Thanks
prev parent reply other threads:[~2014-02-12 7:40 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-02-11 14:25 [PATCH] tun: use netif_receive_skb instead of netif_rx_ni Qin Chuanyu
2014-02-11 15:24 ` Eric Dumazet
2014-02-11 15:47 ` Michael S. Tsirkin
2014-02-12 1:50 ` Qin Chuanyu
2014-02-16 13:03 ` Herbert Xu
2014-02-12 5:28 ` Jason Wang
2014-02-12 5:47 ` Eric Dumazet
2014-02-12 5:50 ` Jason Wang
2014-02-12 6:26 ` Eric Dumazet
2014-02-12 7:38 ` Jason Wang
2014-02-12 6:46 ` Qin Chuanyu
2014-02-12 7:40 ` Jason Wang [this message]
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