Re: Best example for showing throughput?

[Patrick Mahan <mahan-5dHXHCkEAVbYtjvyW6yDsg@public.gmane.org>]

On May 24, 2013, at 8:45 AM, Thomas Monjalon <thomas.monjalon-pdR9zngts4EAvxtiuMwx3w@public.gmane.org> wrote:

> Adding other questions about packet generator:
> 
> 24/05/2013 16:41, Thomas Monjalon :
>> 24/05/2013 16:11, Patrick Mahan :
>>> Intel Xeon E5-2690 (8 physical, 16 virtual)
>> 
>> How many CPU sockets have you ?
>> 
>>> 64 Gbyte DDR3 memory
>>> Intel 82599EB-SPF dual port 10GE interface
>>> CentOS 6.4 (2.6.32-358.6.1.el6.x86_64)
>>> The 82599 is in a 16x PCI-e slot.
>> 
>> Check the datasheet of your motherboard.
>> Are you sure it is wired as a 16x PCI-e ?
>> Is it connected to the right NUMA node ?
>> 
>>> I have it attached to an IXIA box.
> 
> Which packet size are you sending with your packet generator ?
> In case of 64 byte packets (with Ethernet CRC), (64+20)*8 = 672 bits.
> So line rate is 10000/672 = 14.88 Mpps.
> This bandwith should be supported by your 82599 NIC.

Yes, the Ixia is sending the standard 64 byte packet.  The stats show a send rate of 14.880 Mpps.

> 
> Are you sending and receiving on the 2 ports at the same time ?
> Forwarding in the 2 directions is equivalent to double the bandwidth.
> Maybe that 14.88*2 = 29.76 Mpps is too much for your hardware.
> 

Yes I am running traffic both ways.  Interestingly, the amount of drops seem consistent in both directions.  This makes sense since testpmd is spinning off a thread to read from each input queue.

> You could also try with 2 ports on 2 different NICs.

Hmmm, not sure if I can lay hands on another 82599 card.  This one is a loaner.

Thanks,

Patrick

> 
>>> I have been running the app 'testpmd'
>>> in iofwd mode with 2K rx/tx descriptors and 512 burst/mbcache.  I have
>>> been varying the # of queues and unfortunately, I am not seeing full
>>> line rate.
>> 
>> What is your command line ?
>> 
>>> I am seeing about 20-24% droppage on the receive side.  It doesn't seem
>>> to matter the # of queues.
>> 
>> If queues are polled by different cores, it should matter.
>> 
>>> Question 1: Is 'testpmd' the best application for this type of testing? 
>>> If not, which program?  Or do I need to roll my own?
>> 
>> testpmd is the right application for performance benchmark.
>> It is also possible to use examples l2fwd/l3fwd but you should keep
>> testpmd.
>> 
>>> Question 2: I have blacklisted the Intel i350 ports on the motherboard
>>> and am using ssh to access the platform.  Could this be affecting the
>>> test?
>> 
>> You mean i350 is used for ssh ? It shouldn't significantly affect your
>> test.
> 
> -- 
> Thomas