From: Stefan Hajnoczi <stefanha@gmail.com>
To: Vincent Autefage <899140@bugs.launchpad.net>
Cc: qemu-devel@nongnu.org, "Michael S. Tsirkin" <mst@redhat.com>
Subject: Re: [Qemu-devel] [Bug 899140] Re: Problem with Linux Kernel Traffic Control
Date: Fri, 16 Dec 2011 08:31:03 +0000 [thread overview]
Message-ID: <20111216083103.GA24925@stefanha-thinkpad.localdomain> (raw)
In-Reply-To: <4EEA25B0.8030705@labri.fr>
On Thu, Dec 15, 2011 at 04:48:13PM -0000, Vincent Autefage wrote:
> Here is the problem !
>
> The Ubuntu version works only because it not uses an *Intel e1000* but a
> *rtl8139*.
> Therefore, the problem about the e1000 is present in *all* version
> (original or ubuntu ones).
>
> Thus, the file *e1000.c* must contain some instructions which imply the
> bad TC behavior.
You are right! Looking back at your QEMU command-line you are not
explicitly specifying the NIC model so the default will take effect.
Now we're back to square one: e1000.c performs poorly when the tc
command you posted is used. We don't know why yet.
Michael: Have you ever encountered unexpectedly low throughput when tc
is used inside the guest?
# tc qdisc add dev eth0 root tbf rate 20mbit burst 20k latency 50ms
The observed throughput from iperf is only 100kbit/s, not around
20mbit/s as expected. When tc is not run inside the guest then the NIC
saturates 20mbit/s easily.
Stefan
next prev parent reply other threads:[~2011-12-16 9:27 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-12-02 12:57 [Qemu-devel] [Bug 899140] [NEW] Problem with Linux Kernel Traffic Control Vincent Autefage
2011-12-02 13:10 ` [Qemu-devel] [Bug 899140] " Vincent Autefage
2011-12-02 13:34 ` Stefan Hajnoczi
2011-12-02 14:42 ` Vincent Autefage
2011-12-03 18:48 ` Stefan Hajnoczi
2011-12-04 15:54 ` Vincent Autefage
2011-12-05 8:26 ` Stefan Hajnoczi
2011-12-05 10:45 ` Vincent Autefage
2011-12-05 11:11 ` Stefan Hajnoczi
2011-12-05 12:24 ` Vincent Autefage
2011-12-07 10:57 ` Vincent Autefage
2011-12-14 13:36 ` Vincent Autefage
2011-12-14 14:32 ` Stefan Hajnoczi
2011-12-14 14:27 ` Vincent Autefage
2011-12-14 14:42 ` Vincent Autefage
2011-12-15 8:07 ` Stefan Hajnoczi
2011-12-15 15:03 ` Vincent Autefage
2011-12-15 16:09 ` Stefan Hajnoczi
2011-12-15 16:12 ` Stefan Hajnoczi
2011-12-15 16:48 ` Vincent Autefage
2011-12-16 8:31 ` Stefan Hajnoczi [this message]
2012-01-29 4:49 ` Henrique Rodrigues
2012-01-30 16:30 ` Vincent Autefage
2012-01-31 4:49 ` Henrique Rodrigues
2012-02-09 19:05 ` Henrique Rodrigues
2012-02-10 9:25 ` Vincent Autefage
2017-02-07 12:47 ` Thomas Huth
2017-04-09 4:17 ` Launchpad Bug Tracker
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