Re: [Bloat] Best practices for paced TCP on Linux?

["Roger Jørgensen" <rogerj@gmail.com>]

On Sat, Apr 14, 2012 at 2:35 AM, Rick Jones <rick.jones2@hp.com> wrote:
> On 04/06/2012 03:21 PM, Steinar H. Gunderson wrote:
>> On Fri, Apr 06, 2012 at 02:49:38PM -0700, Dave Taht wrote:
>>> However in your environment you will need the beefed up SFQ that is in
>>> 3.3.
>>> and BQL. If you are not saturating that 10GigE card, you can turn off
>>> TSO/GSO
>>> as well.
>> We're not anywhere near saturating our 10GigE card, and even if we did, we
>> could add at least one 10GigE card more.
>
> TSO/GSO isn't so much about saturating the 10 GbE NIC as it is avoiding
> saturating the CPU(s) driving the 10 GbE NIC.  That is, they save trips down
> the protocol stack, saving CPU cycles.  So, if you are not saturating one or
> more of the CPUs in the system, disabling TSO/GSO should not affect your
> ability to drive bits out the NIC.

What will happen in a virtual only environment when all the VM's got
more than one 10Gbps and you push close to 10Gbps through each VM?
like heavy iperf between lots of the VM's?
Unless the platform does something that should start to saturate some
of the CPU core's in the entire playform.


... kinda make me want to test it out since I got a 10Gbps only
environment (Cisco UCS+Nexus5K) with VMware and there are not much
production traffic there yet...



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