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

From: Willem de Bruijn <willemdebruijn.kernel@gmail.com>
To: Jason Wang <jasowang@redhat.com>
Cc: Network Development <netdev@vger.kernel.org>,
	Willem de Bruijn <willemb@google.com>,
	virtualization@lists.linux-foundation.org,
	David Miller <davem@davemloft.net>,
	"Michael S. Tsirkin" <mst@redhat.com>
Subject: Re: [PATCH net-next v2 5/5] virtio-net: keep tx interrupts disabled unless kick
Date: Fri, 21 Apr 2017 19:13:57 -0400	[thread overview]
Message-ID: <CAF=yD-LE1q=jYzEWS5aFb3OcNWDEL3agkSm495xC=ns0PJWFqw__8946.12187189541$1493077145$gmane$org@mail.gmail.com> (raw)
In-Reply-To: <CAF=yD-KVwRkkGr=pGDmTTXtrrTuAuD7SmTPVtQuwu9aufoBeEQ@mail.gmail.com>

On Thu, Apr 20, 2017 at 10:03 AM, Willem de Bruijn
<willemdebruijn.kernel@gmail.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.