Re: [Xen-users] The bottleneck of using multinetwork card?

[Pasi Kärkkäinen <pasik@xxxxxx>]

On Mon, Sep 06, 2010 at 02:58:32PM +0800, ma qiang wrote:
>    Sorry, I lost two words.
>     I reboot in bare linux not dom0, and have tested it on the same computer
>    using only one network card. the results show 1000M.
> 

So what do you get from xen dom0? 

Also if your guest is HVM, have you installed PV-on-HVM drivers?
without those drivers the performance will be bad from the guest.

-- Pasi

>    On Mon, Sep 6, 2010 at 2:57 PM, ma qiang <[1]maqiang1984@xxxxxxxxx> wrote:
> 
>      20% is the vm's utilization of cpu, not dom0's.
>      My domU is hvm and centos linux.
>      "test server" is OK, and I have tested is on the same computer using
>      only one network card. the results show 1000M.
> 
>      On Mon, Sep 6, 2010 at 2:50 PM, Pasi Kärkkäinen <[2]pasik@xxxxxx> wrote:
> 
>        On Mon, Sep 06, 2010 at 02:44:59PM +0800, ma qiang wrote:
>        >    > Do you mean 250 Mbit/sec ?
>        >    Yes.
>        >    > You should get much more.. how are you measuring the
>        performance?
>        >    > What benchmark are you using?
>        >    I use an tool from ixia to test the network in the vm.
> 
>        Try using some standard network performance testing tools
>        such as "iperf" or just regular ftp file transfers.
>        >    > Are both the eth0 and eth1 connected to the same network/vlan?
>        >    Yes.  I run my test from another computer to connect to vm0 and
>        vm1,  and
>        >    they all in the same switch.
>        >    To be noted my cards are both 1000m network card.
>        >
> 
>        How is the 'test server' connected?
> 
>        >    > When you run the network benchmark try running "xm top"
>        >    > to monitor the overall cpu usage.. also run "top" in dom0
>        >    > to see if there's a big cpu usage in dom0.
>        >    No, the cpu is less than 20%
> 
>        20% on dom0?
>        How about the domUs? Do they have big cpu usage?
> 
>        What kind of guests do you have? pv? hvm? linux? windows?
> 
>        -- Pasi
>        >    On Mon, Sep 6, 2010 at 2:08 PM, Pasi Kärkkäinen
>        <[1][3]pasik@xxxxxx> wrote:
>        >    > On Mon, Sep 06, 2010 at 01:58:10PM +0800, ma qiang wrote:
>        >    >> Hi all,
>        >    >>     I have install xen 3.4.3 based on centos5.4.
>        >    >>     I changed a line in /etc/xen/xend-config.sxp like below:
>        >    >> (network-script network-bridge)   ---->    (network-script
>        >    my-network-bridge)
>        >    >>
>        >    >> and #cat /etc/xen/scripts/my-network-script prints as below:
>        >    >> #!/bin/sh
>        >    >> /etc/xen/scripts/network-bridge "$@" netdev=eth0 bridge=eth0
>        >    >> /etc/xen/scripts/network-bridge "$@" netdev=eth1 bridge=eth1
>        >    >>
>        >    >> Now I installed two vms, and set one vm using eth0, then set
>        the other
>        >    >> using eth1.
>        >    >> So, I can connect internet in both vms.
>        >    >>
>        >    >> But now my problem is that the throughput of two network card
>        is the
>        >    >> same as only one network card.
>        >    >> Another words, If I use the only one network card such as eth0
>        for the
>        >    >> two vms, the throughput of eth0 is about 250m.
>        >    >> But when I set one vm use eth0 and the other use eth1, the
>        total
>        >    >> throughput of eth0 and eth1 is about 250m too.
>        >    >>
>        >    >> That why?  Any bottleneck?
>        >    >> Thanks a lot.
>        >    >>
>        >    >
>        >    > Do you mean 250 Mbit/sec ?
>        >    >
>        >    > You should get much more.. how are you measuring the
>        performance?
>        >    > What benchmark are you using?
>        >    >
>        >    > Are both the eth0 and eth1 connected to the same network/vlan?
>        >    >
>        >    > When you run the network benchmark try running "xm top"
>        >    > to monitor the overall cpu usage.. also run "top" in dom0
>        >    > to see if there's a big cpu usage in dom0.
>        >    >
>        >    > -- Pasi
>        >    >
>        >    >
>        >
>        > References
>        >
>        >    Visible links
>        >    1. mailto:[4]pasik@xxxxxx
> 
> References
> 
>    Visible links
>    1. mailto:maqiang1984@xxxxxxxxx
>    2. mailto:pasik@xxxxxx
>    3. mailto:pasik@xxxxxx
>    4. mailto:pasik@xxxxxx

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