[vbox-dev] Updating network interfaces list speed-up

a.urakov at drweb.com a.urakov at drweb.com
Wed Apr 15 06:24:59 UTC 2015


Hi Klaus,

thanks a lot!

Regards,
Alexander

14.04.2015 22:33, Klaus Espenlaub пишет:
> Hi Alexander,
>
> 5.0.0BETA2 will contain a modification inspired by your patch, which 
> should actually lower the time during which the lock is held even further.
>
> There would be ways to optimize it much further (I left a todo comment 
> in the code hinting what needs doing and what the difficulties are), 
> but decided against doing it now.
>
> Klaus
>
> On 08.04.2015 14:32, a.urakov at drweb.com wrote:
>> Hello,
>>
>> I just want to remind about this patch...
>>
>> Regards,
>> Alexander
>>
>> 25.02.2015 16:16, a.urakov at drweb.com пишет:
>>> Hello!
>>>
>>> We would like to contribute to VirtualBox under MIT license. We want 
>>> to suggest our changes for multiple VMs starting speed-up.
>>>
>>> The basic idea is to take out getting of host interfaces from write 
>>> lock on host object. When many VMs are starting at the same time 
>>> then /FindHostNetworkInterfaceByName/ is called for every machine 
>>> and it updates network interfaces. So if umount of VMs is large 
>>> enough then execution time of this function greatly increases due to 
>>> lock wait.
>>>
>>> There are two /VBoxSVC/ logs in attach: before applying our changes 
>>> and after it. In every case we started 80 VMs at the same time. 
>>> Statistic of /FindHostNetworkInterfaceByName/ execution time before 
>>> changes is:
>>>
>>> Min: 0.38 s (nspr-31)
>>> Med: 14.13 s (nspr-82)
>>> Max: 37.70 s (nspr-188)
>>> Avg: 15.07 s
>>>
>>> Statistic after changes is:
>>>
>>> Min: 1.12 s (nspr-85)
>>> Med: 6.56 s (nspr-228)
>>> Max: 17.27 s (nspr-7)
>>> Avg: 5.82 s
>>>
>>> Regards,
>>> Alexander 
>
>
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