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: 22+ 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 14:04 ` Rusty Russell
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
2009-06-08 5:22 ` Herbert Xu
2009-06-13 12:30 ` Rusty Russell
2009-06-14 6:45 ` Herbert Xu
2009-06-18 7:17 ` Rusty Russell
2009-06-18 7:34 ` Herbert Xu
2009-06-19 3:37 ` Rusty Russell
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 5:46 ` Krishna Kumar2
2009-06-22 7:34 ` Herbert Xu
2009-06-22 13:41 ` Krishna Kumar2
2009-06-22 18:25 ` Matt Carlson
2009-06-23 2:54 ` Herbert Xu
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=200906221209.16481.rusty@rustcorp.com.au \
--to=rusty@rustcorp$(echo .)com.au \
--cc=davem@davemloft$(echo .)net \
--cc=herbert@gondor$(echo .)apana.org.au \
--cc=mcarlson@broadcom$(echo .)com \
--cc=netdev@vger$(echo .)kernel.org \
--cc=virtualization@lists$(echo .)linux-foundation.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox