Limitation of Ostinator traffic generator ??

[Venkat Vangala]

Hi,

I am using the Ostinato 0.8 release on Ubuntu 14.04. First of all I thank the team for a very good tool. 

I am testing for 10G/30G traffic. 

I see difference in performance when compared to IPERF3. Please clarify.

I connected Mellanox Cx3 40G cards in Two PCs and trying to test the traffic rate between them.

When I test with IPERF3, I see around 25G bidirectional. But when I test with Ostinato I am seeing maximum of approx. 10G.

As I see from FAQs etc., there is no limit of Ostinato for the maximum traffic generation. Is this correct ?

If yes, Could you please help in answering/clarifying the issue I am facing ?

Thanks for your help.

-Venkat

[Srivats P]

Iperf and Ostinato employ different ways to generate the traffic.

My guess is (I haven't checked the code), iperf likely uses tcp/udp
sockets - this will allow it to send a larger buffer from user space
to kernel space that may span multiple packets. Iperf can only specify
the payload of the TCP/UDP header so it can use the Kernel provided
TCP/UDP sockets.

Ostinato crafts the entire frame from Ether to IP to TCP/UDP and
payload. Because of this Ostinato cannot use TCP/UDP sockets. Instead
it uses the PCAP library to send the packets (which is likely using a
raw socket underneath). The PCAP API allows us to send only a single
packet in one call.

There was another thread sometime back which reported something similar.

There may be other differences also leading to the performance
difference. I haven't had a chance (or motivation) to investigate this
till now.

Srivats

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[Venkat Vangala]

Thanks Srivats. Could you please let me know the maximum packet data rate that Ostinato can sustain in a high performing PCs ( HP Z640 Server class PCs).

Thanks

-Venkat

> email to ostinato+unsubscribe@googlegroups.com.

[Srivats P]

As specified in the FAQ the maximum packet rate is a function of
several variables so it is not possible to quote a specific number.

You can however, search the mailing list archives for what people have
achieved with their configurations.

One example is https://groups.google.com/d/msg/ostinato/ZdiR2ZXdt0c/dra1E7kjBAAJ.
There maybe more in the mailing list archives.

Srivats

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