A problem on TCP in High RTT Environment.

[Michael Tuexen]

On 11 Aug 2014, at 09:32, Niu Zhixiong <kaiaixi at gmail.com> wrote:

> Thanks for your reminding. I tried hw.igb.num_queues=2 just now. But, the throughput is still slow. And When I tested same things in my Virtual machine-based environment(use Virtio), the throughput is similar(SCTP is 2x than TCP).
So is the curve still the same or is it now constantly half of the SCTP throughput which
was almost constant for different RTTs...

Best regards
Michael
> 
> Regards,
> Niu Zhixiong
> －－－－－－－－－－－－－－－
>  kaiaixi at gmail.com
> 
> 
> On Mon, Aug 11, 2014 at 3:08 PM, Eggert, Lars <lars at netapp.com> wrote:
> Hi,
> 
> On 2014-8-10, at 5:48, Niu Zhixiong <kaiaixi at gmail.com> wrote:
> > I am using Intel I350-T4 NIC.
> 
> igb driver?
> 
> I've been having weird issues with this driver under 10-RELEASE, too. On one machine, I had to limit hw.igb.num_queues=2 in order to get any sort of useful connectivity. On another machine, I had to severely bump kern.ipc.nmbclusters & friends. I'm not sure this is the issue here, since SCTP seems to be working OK, but I'm not trusting igb NICs at the moment.
> 
> Lars
>