From: "Michael S. Tsirkin" <mst@redhat.com>
To: Jesper Dangaard Brouer <brouer@redhat.com>
Cc: Jason Wang <jasowang@redhat.com>,
davem@davemloft.net, netdev@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH net-next] tuntap: introduce tx skb ring
Date: Wed, 18 May 2016 11:21:59 +0300 [thread overview]
Message-ID: <20160518112045-mutt-send-email-mst@redhat.com> (raw)
In-Reply-To: <20160518101631.368e3447@redhat.com>
On Wed, May 18, 2016 at 10:16:31AM +0200, Jesper Dangaard Brouer wrote:
>
> On Tue, 17 May 2016 09:38:37 +0800 Jason Wang <jasowang@redhat.com> wrote:
>
> > >> And if tx_queue_length is not power of 2,
> > >> we probably need modulus to calculate the capacity.
> > > Is that really that important for speed?
> >
> > Not sure, I can test.
>
> In my experience, yes, adding a modulus does affect performance.
How about simple
if (unlikely(++idx > size))
idx = 0;
> >
> > Right, this sounds a good solution.
>
> Good idea.
I'm not that sure - it's clearly wasting memory.
> --
> Best regards,
> Jesper Dangaard Brouer
> MSc.CS, Principal Kernel Engineer at Red Hat
> Author of http://www.iptv-analyzer.org
> LinkedIn: http://www.linkedin.com/in/brouer
next prev parent reply other threads:[~2016-05-18 8:21 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-16 1:17 [PATCH net-next] tuntap: introduce tx skb ring Jason Wang
2016-05-16 3:56 ` Eric Dumazet
2016-05-16 7:51 ` Jason Wang
2016-05-18 8:13 ` Jesper Dangaard Brouer
2016-05-18 8:23 ` Michael S. Tsirkin
2016-05-18 10:23 ` Jason Wang
2016-05-18 11:52 ` Steven Rostedt
2016-05-18 16:26 ` Michael S. Tsirkin
2016-05-18 16:41 ` Eric Dumazet
2016-05-18 16:46 ` Michael S. Tsirkin
2016-05-19 11:59 ` Jesper Dangaard Brouer
2016-05-16 4:23 ` Michael S. Tsirkin
2016-05-16 7:52 ` Jason Wang
2016-05-16 8:08 ` Michael S. Tsirkin
2016-05-17 1:38 ` Jason Wang
2016-05-18 8:16 ` Jesper Dangaard Brouer
2016-05-18 8:21 ` Michael S. Tsirkin [this message]
2016-05-18 9:21 ` Jesper Dangaard Brouer
2016-05-18 9:55 ` Michael S. Tsirkin
2016-05-18 10:42 ` Jason Wang
2016-05-18 10:58 ` Michael S. Tsirkin
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