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Re: [Qemu-devel] Hitting 29 NIC limit
From: |
Markus Armbruster |
Subject: |
Re: [Qemu-devel] Hitting 29 NIC limit |
Date: |
Thu, 14 Oct 2010 14:36:19 +0200 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/23.1 (gnu/linux) |
Avi Kivity <address@hidden> writes:
> On 10/14/2010 12:54 AM, Anthony Liguori wrote:
>> On 10/13/2010 05:32 PM, Anjali Kulkarni wrote:
>>>
>>> Hi,
>>>
>>> Using the legacy way of starting up NICs, I am hitting a limitation
>>> after 29
>>> NICs ie no more than 29 are detected (that's because of the 32 PCI slot
>>> limit on a single bus- 3 are already taken up)
>>> I had initially increased the MAX_NICS to 48, just on my tree, to get to
>>> more, but ofcource that wont work.
>>> Is there any way to go beyond 29 NICs the legacy way? What is the
>>> maximum
>>> that can be supported by the qdev mothod?
>>
>> I got up to 104 without trying very hard using the following script:
>>
>> args=""
>> for slot in 5 6 7 8 9 10 11 12 13 14 15 16 17; do
>> for fn in 0 1 2 3 4 5 6 7; do
>> args="$args -netdev user,id=eth${slot}_${fn}"
>> args="$args -device
>> virtio-net-pci,addr=${slot}.${fn},netdev=eth${slot}_${fn},multifunction=on,romfile="
>> done
>> done
>>
>> x86_64-softmmu/qemu-system-x86_64 -hda ~/images/linux.img ${args}
>> -enable-kvm
>>
>> The key is to make the virtio-net devices multifunction and to fill
>> out all 8 functions for each slot.
I'm amazed that works. Can't see how creating another qdev in the same
slot makes a proper multifunction device.
> This is unlikely to work right wrt pci hotplug. If we want to support
> a large number of interfaces, we need true multiport cards.
Indeed. As far as I know, we can't hot plug multifunction PCI devices.
> What's the motivation for such a huge number of interfaces?
- Re: [Qemu-devel] Hitting 29 NIC limit, (continued)
- Re: [Qemu-devel] Hitting 29 NIC limit, Richard W.M. Jones, 2010/10/14
- Re: [Qemu-devel] Hitting 29 NIC limit, Anthony Liguori, 2010/10/14
- Re: [Qemu-devel] Hitting 29 NIC limit, Richard W.M. Jones, 2010/10/14
- Re: [Qemu-devel] Hitting 29 NIC limit, Anjali Kulkarni, 2010/10/14
- Re: [Qemu-devel] Hitting 29 NIC limit, Anthony Liguori, 2010/10/14
- Re: [Qemu-devel] Hitting 29 NIC limit, Anjali Kulkarni, 2010/10/14
- Re: [Qemu-devel] Hitting 29 NIC limit, Anthony Liguori, 2010/10/14
- Re: [Qemu-devel] Hitting 29 NIC limit,
Markus Armbruster <=
- Re: [Qemu-devel] Hitting 29 NIC limit, Anthony Liguori, 2010/10/14
- Re: [Qemu-devel] Hitting 29 NIC limit, Markus Armbruster, 2010/10/15
- [Qemu-devel] Passing in additional info to guest OS and e1000 test suite?, Anjali Kulkarni, 2010/10/15
- [Qemu-devel] Re: Passing in additional info to guest OS and e1000 test suite?, Anthony Liguori, 2010/10/15
- Re: [Qemu-devel] Hitting 29 NIC limit, Anthony Liguori, 2010/10/14
- Re: [Qemu-devel] Hitting 29 NIC limit, Avi Kivity, 2010/10/14
- Re: [Qemu-devel] Hitting 29 NIC limit, Anthony Liguori, 2010/10/14
- Re: [Qemu-devel] Hitting 29 NIC limit, Avi Kivity, 2010/10/14