From: Rusty Russell <rusty@rustcorp.com.au>
To: Herbert Xu <herbert@gondor.apana.org.au>
Cc: netdev@vger.kernel.org,
virtualization@lists.linux-foundation.org,
David Miller <davem@davemloft.net>,
Matt Carlson <mcarlson@broadcom.com>
Subject: Re: [PATCH 2/4] virtio_net: return NETDEV_TX_BUSY instead of queueing an extra skb.
Date: Mon, 22 Jun 2009 12:09:15 +0930 [thread overview]
Message-ID: <200906221209.16481.rusty@rustcorp.com.au> (raw)
In-Reply-To: <20090619141014.GA19828@gondor.apana.org.au>
On Fri, 19 Jun 2009 11:40:14 pm Herbert Xu wrote:
> > On the other hand, we're underutilizing the queue to avoid it. I find
> > that a little embarrassing.
>
> Here's why I think this is not an issue. If your NIC is high
> bandwidth then your ring is going to have to be huge so the
> amount that is underutilised (a 64K packet) is tiny. If your
> NIC is low bandwidth then this is where you often need QoS and
> in that case you do *NOT* want to fully utilise the HW queue.
Well, we leave that up to the NIC designer. It's retro-justification for
throwing away a few percent of the queue, but the QoS issue is even more in
the noise.
But I will give in now and change virtio_net to use this substandard API :(
Thanks,
Rusty.
next prev parent reply other threads:[~2009-06-22 2:39 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-05-29 14:16 [PATCH 2/4] virtio_net: return NETDEV_TX_BUSY instead of queueing an extra skb Rusty Russell
2009-06-02 8:07 ` Mark McLoughlin
2009-06-02 8:07 ` Mark McLoughlin
2009-06-02 14:04 ` Rusty Russell
2009-06-02 14:04 ` Rusty Russell
2009-06-02 9:05 ` Herbert Xu
2009-06-02 9:05 ` Herbert Xu
2009-06-02 13:55 ` Rusty Russell
2009-06-02 23:45 ` Herbert Xu
2009-06-03 3:17 ` Rusty Russell
2009-06-03 3:17 ` Rusty Russell
2009-06-08 5:22 ` Herbert Xu
2009-06-13 12:30 ` Rusty Russell
2009-06-14 6:45 ` Herbert Xu
2009-06-14 6:45 ` Herbert Xu
2009-06-18 7:17 ` Rusty Russell
2009-06-18 7:17 ` Rusty Russell
2009-06-18 7:34 ` Herbert Xu
2009-06-19 3:37 ` Rusty Russell
2009-06-19 3:37 ` Rusty Russell
2009-06-19 4:36 ` Herbert Xu
2009-06-19 4:36 ` Herbert Xu
2009-06-19 13:50 ` Rusty Russell
2009-06-19 14:10 ` Herbert Xu
2009-06-22 2:39 ` Rusty Russell [this message]
2009-06-22 2:39 ` Rusty Russell
2009-06-19 14:10 ` Herbert Xu
2009-06-19 13:50 ` Rusty Russell
2009-06-22 5:46 ` Krishna Kumar2
2009-06-22 5:46 ` Krishna Kumar2
2009-06-22 7:34 ` Herbert Xu
2009-06-22 7:34 ` Herbert Xu
2009-06-22 13:41 ` Krishna Kumar2
2009-06-22 13:41 ` Krishna Kumar2
2009-06-22 18:25 ` Matt Carlson
2009-06-23 2:54 ` Herbert Xu
2009-06-23 2:54 ` Herbert Xu
2009-06-22 18:25 ` Matt Carlson
2009-06-18 7:34 ` Herbert Xu
2009-06-13 12:30 ` Rusty Russell
2009-06-08 5:22 ` Herbert Xu
2009-06-02 23:45 ` Herbert Xu
2009-06-02 13:55 ` Rusty Russell
-- strict thread matches above, loose matches on Subject: below --
2009-05-29 14:16 Rusty Russell
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