netdev - Re: [PATCH net-next v2 5/5] virtio-net: keep tx interrupts disabled unless kick

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Message-ID: <CAF=yD-LE1q=jYzEWS5aFb3OcNWDEL3agkSm495xC=ns0PJWFqw@mail.gmail.com>
Date:   Fri, 21 Apr 2017 19:13:57 -0400
From:   Willem de Bruijn <willemdebruijn.kernel@...il.com>
To:     Jason Wang <jasowang@...hat.com>
Cc:     Network Development <netdev@...r.kernel.org>,
        "Michael S. Tsirkin" <mst@...hat.com>,
        virtualization@...ts.linux-foundation.org,
        David Miller <davem@...emloft.net>,
        Willem de Bruijn <willemb@...gle.com>
Subject: Re: [PATCH net-next v2 5/5] virtio-net: keep tx interrupts disabled
 unless kick

On Thu, Apr 20, 2017 at 10:03 AM, Willem de Bruijn
<willemdebruijn.kernel@...il.com> wrote:
>>> -       if (!use_napi)
>>> +       if (use_napi) {
>>> +               if (kick)
>>> +                       virtqueue_enable_cb_delayed(sq->vq);
>>> +               else
>>> +                       virtqueue_disable_cb(sq->vq);
>>
>>
>> Since virtqueue_disable_cb() do nothing for event idx. I wonder whether or
>> not just calling enable_cb_dealyed() is ok here.
>
> Good point.
>
>> Btw, it does not disable interrupt at all, I propose a patch in the past
>> which can do more than this:
>>
>> https://patchwork.kernel.org/patch/6472601/
>
> Interesting. Yes, let me evaluate that variant.

In initial tests I don't see a significant change, but we can look
into this more closely as a follow-on patch.