perfSONAR User Q&A and Other Discussion

["Uhl, George D. (GSFC-423.0)[SGT INC]" <>]

When I was researching the Liva X capabilities I ran across an email from Larry Blunk of Merit that he posted on the list this past October.

  One thing to note is that Ubuntu enables the "ondemand" init script

by default which puts the CPU in "powersave" mode.   In testing the

LIVA, I found that this seems to limit throughput a bit in performance

tests.  I get around 900Mbps TCP throughput vs. 940Mbps in

"performance" mode.  Also saw some packet loss when doing UDP tests

with 1500 byte datagrams at 1 Gbps in powersave mode.  You can disable

the script with the following which will leave the CPU in performance

mode.

update-rc.d -f ondemand remove

-Larry Blunk

  Merit

Disabling the “ondemand” mode capability might work for you.   I did it and I was able to achieve 940 Mbps.

-George

From: <> on behalf of Brian Tierney <>
Reply-To: "" <>
Date: Tuesday, December 22, 2015 at 1:12 PM
To: Daniel Doyle <>
Cc: Hyojoon Kim <>, "" <>
Subject: Re: [perfsonar-user] Bandwidth measurement with LIVA X 2GB/32GB eMMC

On Tue, Dec 22, 2015 at 12:00 PM, Daniel Doyle <> wrote:

Hi Joon,

Sorry to hear about that. A couple of questions / debugging ideas:

- Are you seeing this in both directions?
- Have you tried using the same port with a different device?
- If you're using / not using jumbo frames has the device been configured accordingly?

fwiw, I did not apply any tunings out of the box on a LIVA X and got >900Mbps on a local network. It's possible some of those tunings might not be appropriate for a machine like that, but I have't dug into it.

I agree that might be the issue. The tunings on fasterdata might not be right for a small node.

See if the original default debian settings are better.

 

-Dan

> On Dec 22, 2015, at 11:58 AM, Hyojoon Kim <> wrote:
>
> Hi all,
>
> We decided to play with a LIVA X 2GB/32GB eMMC node with perfSONAR 3.5. However, I am getting around 535Mbps instead of 940+Mbps when I initiate a bwctl test to another local perfSONAR node we have. Between two Dell R610 servers with perfSONAR, we do get over 950Mbps, so it’s likely not a network problem.
>
> I have generally followed the instructions here (http://docs.perfsonar.net/install_debian.html), and installed three packages:
> apt-get install perfsonar-testpoint
> apt-get install perfsonar-toolkit-security
> apt-get install perfsonar-toolkit-sysctl
>
> I also did the Linux Tuning, which is indicated here:
> http://fasterdata.es.net/host-tuning/linux/
>
> Does anyone know what I am missing? I do have Ubuntu 14.04.3 Desktop OS on this. Maybe switching to the well-tested Ubuntu 12.04 is better?
>
> ===
> $ lsb_release -a
> No LSB modules are available.
> Distributor ID: Ubuntu
> Description:    Ubuntu 14.04.3 LTS
> Release:        14.04
> Codename:       trusty
>
> $ uname -a
> Linux perfbox-livaxtest-01 3.19.0-39-generic #44~14.04.1-Ubuntu SMP Wed Dec 2 10:00:35 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux
> ===
>
> Thanks,
> Joon

Dan Doyle
GlobalNOC Software Developer
1-812-856-3892

--

Brian Tierney, http://www.es.net/tierney
Energy Sciences Network (ESnet), Berkeley National Lab
http://fasterdata.es.net