How do I balance bandwidth over several virtual NICs?

Luigi Rizzo rizzo at iet.unipi.it
Tue Sep 23 16:40:19 UTC 2014


On Tuesday, September 23, 2014, Alexander V. Chernikov <melifaro at freebsd.org>
wrote:

> On 23.09.2014 20:00, Adrian Chadd wrote:
>
>> Ah, this behaviour.
>>
>> It's called DROP_EN on the intel igb / ixgbe hardware. Grep the
>> drivers for that particular register bit/setting.
>>
>> Set that bit for an RX queue and it'll instruct the MAC to drop frames
>> destined if that RX ring is full to it and keep receiving on the other
>> rings. Otherwise yes, receiving on that ring with the ring full cuases
>> the MAC to stop receiving on all rings until that ring has free space.
>>
>> You flip this on with ixgbe and igb by disabling tx/rx flowcontrol
>> (sysctl dev.ix|igb.X.fc=0) before configuring the interface.
>>
> Oh, cool.
> Yet another reason to turn flow control off by default.


Or at least decouple the two features.

Cheers
Luigi


>
>>
>>
>> -a
>>
>>
>

-- 
-----------------------------------------+-------------------------------
 Prof. Luigi RIZZO, rizzo at iet.unipi.it  . Dip. di Ing. dell'Informazione
 http://www.iet.unipi.it/~luigi/        . Universita` di Pisa
 TEL      +39-050-2211611               . via Diotisalvi 2
 Mobile   +39-338-6809875               . 56122 PISA (Italy)
-----------------------------------------+-------------------------------


More information about the freebsd-net mailing list