Re: [Qemu-devel] >256 Virtio-net-pci hotplug Devices

[Marcel Apfelbaum <marcel@redhat.com>]

On 25/07/2017 21:00, Kinsella, Ray wrote:
> 
> Hi Marcel,
>

Hi Ray,

> On 24/07/2017 00:14, Marcel Apfelbaum wrote:
>> On 24/07/2017 7:53, Kinsella, Ray wrote:
>>
>> Even if I am not aware of how much time would take to init a bare-metal
>> PCIe Root Port, it seems too much.
>>
> 
> So I repeated the testing for 64, 128, 256 and 512 ports. I ensured the 
> configuration was sane, that 128 was twice the number of root ports and 
> virtio-pci-net devices as 64.
> 
> I got the following results - shown in seconds, as you can see it is non 
> linear but not exponential, there is something that is not scaling well.
> 
>          64    128    256    512
> PCIe Root Ports    14    72    430    2672
> ACPI        4    35    342    3863
> Loading Drivers    1    1    31    621
> Total Boot    34    137    890    7516
> 
> ( I did try to test 1024 devices, but it just dies silently )
> 
> Ray K
> 

It is an issue worth looking into it, one more question,
all the measurements are from OS boot? Do you use SeaBIOS?
No problems with the firmware?

Thanks,
Marcel