Can I limit number of rx queues for igb (and other Intel drivers)?

Can I limit number of rx queues for igb (and other Intel drivers)?

[Ben Greear]

I'm using pktgen to send a stream of packets with varying source and destination
IP addresses.  It appears that the fancy rx logic of the NIC (I'm using igb for this test)
causes the received packets to appear on random rx queues and so be received out
of order in the network core.

I do not see the out-of-order issue when using a single source/dest IP address
for the pktgen packets.

So, is there a way to tell igb to use only a single rx queue?

Thanks,
Ben

-- 
Ben Greear <greearb@candelatech.com>
Candela Technologies Inc  http://www.candelatech.com

RE: Can I limit number of rx queues for igb (and other Intel drivers)?

[Wyborny, Carolyn]

 

>-----Original Message-----
>From: netdev-owner@vger.kernel.org 
>[mailto:netdev-owner@vger.kernel.org] On Behalf Of Ben Greear
>Sent: Friday, June 18, 2010 3:40 PM
>To: NetDev
>Subject: Can I limit number of rx queues for igb (and other 
>Intel drivers)?
>
>I'm using pktgen to send a stream of packets with varying 
>source and destination
>IP addresses.  It appears that the fancy rx logic of the NIC 
>(I'm using igb for this test)
>causes the received packets to appear on random rx queues and 
>so be received out
>of order in the network core.
>
>I do not see the out-of-order issue when using a single 
>source/dest IP address
>for the pktgen packets.
>
>So, is there a way to tell igb to use only a single rx queue?
>
>Thanks,
>Ben
>
>-- 
>Ben Greear <greearb@candelatech.com>
>Candela Technologies Inc  http://www.candelatech.com
>
>--
>To unsubscribe from this list: send the line "unsubscribe netdev" in
>the body of a message to majordomo@vger.kernel.org
>More majordomo info at  http://vger.kernel.org/majordomo-info.html
>
Hello,

There is not a way to tell igb to use a single queue and ethtool does not currently have a way to do this.

We also maintain an out of kernel version of the driver at SourceForge that has module parameters to do this.  

If you need to do this with the kernel version, we'd need to modify ethtool to be able to do this.

Thanks,

Carolyn Wyborny
Carolyn.wyborny@intel.com

Re: Can I limit number of rx queues for igb (and other Intel drivers)?

[Ben Greear]

On 06/21/2010 04:35 PM, Wyborny, Carolyn wrote:
>
>
>> -----Original Message-----
>> From: netdev-owner@vger.kernel.org
>> [mailto:netdev-owner@vger.kernel.org] On Behalf Of Ben Greear
>> Sent: Friday, June 18, 2010 3:40 PM
>> To: NetDev
>> Subject: Can I limit number of rx queues for igb (and other
>> Intel drivers)?
>>
>> I'm using pktgen to send a stream of packets with varying
>> source and destination
>> IP addresses.  It appears that the fancy rx logic of the NIC
>> (I'm using igb for this test)
>> causes the received packets to appear on random rx queues and
>> so be received out
>> of order in the network core.
>>
>> I do not see the out-of-order issue when using a single
>> source/dest IP address
>> for the pktgen packets.
>>
>> So, is there a way to tell igb to use only a single rx queue?
>>
>> Thanks,
>> Ben
>>
>> --
>> Ben Greear<greearb@candelatech.com>
>> Candela Technologies Inc  http://www.candelatech.com
>>
>> --
>> To unsubscribe from this list: send the line "unsubscribe netdev" in
>> the body of a message to majordomo@vger.kernel.org
>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>>
> Hello,
>
> There is not a way to tell igb to use a single queue and ethtool does not currently have a way to do this.
>
> We also maintain an out of kernel version of the driver at SourceForge that has module parameters to do this.
>
> If you need to do this with the kernel version, we'd need to modify ethtool to be able to do this.

A module parameter would be OK, but an ethtool command to change this live
would be really nice!  It may be a day or two before I get back to testing
this, but will try your out-of-tree driver with proper mod-parm invocation
then.

Thanks,
Ben

-- 
Ben Greear <greearb@candelatech.com>
Candela Technologies Inc  http://www.candelatech.com