[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-devel] [Bug 899140] Re: Problem with Linux Kernel Traffic Cont
Re: [Qemu-devel] [Bug 899140] Re: Problem with Linux Kernel Traffic Control
Fri, 02 Dec 2011 14:42:14 -0000
So, the host command lines are :
*$ qemu -name A -sdl -m 512 -enable-kvm -localtime -k fr -hda
debian1.img -net nic,macaddr=a0:00:00:00:00:01 -net
The second is
*$ qemu -name B -sdl -m 512 -enable-kvm -localtime -k fr -hda
debian2.img -net nic,macaddr=a0:00:00:00:00:02 -net
On virual machines :
address@hidden ifconfig eth0 192.168.0.1*
address@hidden tc qdisc add dev eth0 root tbf rate 20mbit burst 20480 latency
address@hidden **ifconfig eth0 192.168.0.2*
Then if we check with /Iperf/, the real rate will be about 100kbit/s :
address@hidden iperf -s*
address@hidden iperf -c 192.168.0.1*
Le 02/12/2011 14:34, Stefan Hajnoczi a écrit :
> Hi Vincent,
> Please give steps to reproduce the problem including the QEMU
> command-lines you used and what commands need to be run inside the
> guest and on the host.
You received this bug notification because you are a member of qemu-
devel-ml, which is subscribed to QEMU.
Problem with Linux Kernel Traffic Control
Status in QEMU:
The last main versions of QEMU (0.14.1, 0.15 and 1.0) have an important
problem when running on a Linux distribution which running itself a Traffic
Control (TC) instance.
Indeed, when TC is configured with a Token Bucket Filter (TBF) with a
particular rate, the effective rate is very slower than the desired one.
For instance, lets consider the following configuration :
# tc qdisc add dev eth0 root tbf rate 20mbit burst 20k latency 50ms
The effective rate will be about 100kbit/s ! (verified with iperf)
I've encountered this problem on versions 0.14.1, 0.15 and 1.0 but not with
In the 0.14.0, we have a rate of 19.2 mbit/s which is quiet normal.
I've done the experimentation on several hosts :
- Debian 32bit core i7, 4GB RAM
- Debian 64bit core i7, 8GB RAM
- 3 different high performance servers : Ubuntu 64 bits, 48 AMD Opteron,
128GB of RAM
The problem is always the same... The problem is also seen with a
Class Based Queuing (CBQ) in TC.
To manage notifications about this bug go to:
|[Prev in Thread]
||[Next in Thread]|