Ostinato 1.2 for Ubuntu - Two Issues Input drops and 1Mbps maximum packet generation

[Edwin Mallette]

So I have two issues that I'm looking for a little assistance to resolve.  My Google fu was not successful in determining the cause of either.

First Question - 1Mbps Traffic Generation Maximum...

I'm not sure what I need to do to increase the maximum packet generation rate ... in the Ostinato UI, no matter how I configure my streams - I can select bit rate of 6Mbps all day, but then when it is actually performing traffic generation, 1Mbps..

Is there some configuration option I need to select to be able to generate more than 1Mbps?  I do have a license key but didn't find any place to install said license key.  I do not have the Turbo key but that seems to be only for 10Gbps+.

Second Question - Input Packet Drops on Linux 

So I see a small number (percentage-wise) of input packet drops on Ubuntu.  I'm guessing some buffer needs to be tuned.   I do not see CRCs or anything that would indicate a physical layer issue.  Any suggestions? 

Thanks!

Ed

[Srivats P]

Hi Ed,

First Question - 1Mbps Traffic Generation Maximum...

I'm not sure what I need to do to increase the maximum packet generation rate ... in the Ostinato UI, no matter how I configure my streams - I can select bit rate of 6Mbps all day, but then when it is actually performing traffic generation, 1Mbps..

1Mbps doesn't sound right.

A few questions -

* What is your hardware platform? What are the specs?

* Can you share a screenshot of the Ostinato GUI showing 1 Mbps?

* What is your packet size in the stream? Configure the largest size possible - 1518 (or 9000 if you can support jumbo)

* Can you attach your stream here so that I can take a look?

 

Is there some configuration option I need to select to be able to generate more than 1Mbps?  I do have a license key but didn't find any place to install said license key.  I do not have the Turbo key but that seems to be only for 10Gbps+.

Nothing is needed. 

Second Question - Input Packet Drops on Linux 

So I see a small number (percentage-wise) of input packet drops on Ubuntu.  I'm guessing some buffer needs to be tuned.   I do not see CRCs or anything that would indicate a physical layer issue.  Any suggestions? 

The input drops are NIC and driver dependent, so difficult to diagnose without specifics.

Try increasing your Rx ring size using ethtool if your driver supports it.

Srivats (Creator, Ostinato)

[Edwin Mallette]

Alright, so on 1 - I'm an idiot.  Sometimes I should do this on more sleep.  So what's happening is that I'm attempting to set Ostinato to transmit at 2.5Mbps.  Ostinato is transmitting at the full line rate of the interface (which is 1Gbps.). I was trying to test out a bandwidth policer (I guess the policer's not working) because it was letting the entire 1gbps stream through.  That's what I blame my belief that it was 1mbps, not 1gbps... couldn't count the 0s correctly.

Alright - so then - is there a trick to get Ostinato to actually adhere to the configured transmitting rate ?  It's in the screen shot.

Okay, so I adjusted the RX ring size to the max supported by the driver and no change.  The rate of dropped frames appears to be the same.  However, I stopped transmitting at 2000 bytes (I had a policy set for a fixed frame size of 2000 bytes) and the drops stopped.  It was somewhere around 2% packet loss.

[Srivats P]

Hi Edwin

Alright, so on 1 - I'm an idiot.  Sometimes I should do this on more sleep.  So what's happening is that I'm attempting to set Ostinato to transmit at 2.5Mbps.  Ostinato is transmitting at the full line rate of the interface (which is 1Gbps.). I was trying to test out a bandwidth policer (I guess the policer's not working) because it was letting the entire 1gbps stream through.  That's what I blame my belief that it was 1mbps, not 1gbps... couldn't count the 0s correctly.

Alright - so then - is there a trick to get Ostinato to actually adhere to the configured transmitting rate ?  It's in the screen shot.

No worries, we've all made a mistake counting zeros with or without enough sleep!

There have been some suggestions to include a Mbps/Gbps suffix in the port stats table for rates so that one doesn't have to count zeros and commas - although I don't like that personally, maybe I should put my personal reasons aside and implement it!

That 2.5Mbps configured rate and 1000Mbps actual rate is certainly not correct. Can you check a few things for me?

* What is the rate configured for the enabled stream - is that also 2.5Mbps or 1000Mbps or 0? (I'm trying to see if the problem is in the aggregate bit rate shown for all the streams or in the core packet rate generation logic itself

* Does stopping traffic, clicking on Apply and starting transmit again fix the problem?

In any case, please save the streams and send them to me so that I can try and reproduce locally.

 

Okay, so I adjusted the RX ring size to the max supported by the driver and no change.  The rate of dropped frames appears to be the same.  However, I stopped transmitting at 2000 bytes (I had a policy set for a fixed frame size of 2000 bytes) and the drops stopped.  It was somewhere around 2% packet loss.

Are all RX packets 2000 bytes or only some? Is your interface MTU/MRU set to more than 2000?

Srivats (Creator, Ostinato)

[Srivats P]

Edwin,

Any update on this?

Srivats (Founder, Ostinato)
Generate 🚀 wire speed 10/25/40G traffic with the new Ostinato Turbo add-on!

[Edwin Mallette]

My apologies for taking so long to get back to this...

So if I use the packets send method under stream control, and I specify a packet-per-second rate that roughly lines up with the bit rate I'm attempting to achieve, Ostinato appears to asdhere to that rate.

If I set use Bursts, and set a bit/sec for the burst, Ostinato appears to attempt to transmit at wire rate. I attached multiple screen shots that include the operation.  I did attempt to use the Frame Rate field as well when its set to burst and that has no effect.

[Srivats P]

Hi Edwin,

I'm able to reproduce the problem at my end.

I will investigate and get back to you soon.

Srivats (Founder, Ostinato)
Generate 🚀 wire speed 10/25/40G traffic with the new Ostinato Turbo add-on!

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