[Top][All Lists]

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Discuss-gnuradio] Unexplained out-of-sequence packets...

From: Eric Blossom
Subject: Re: [Discuss-gnuradio] Unexplained out-of-sequence packets...
Date: Wed, 12 May 2010 11:37:13 -0700
User-agent: Mutt/1.5.20 (2009-08-17)

On Wed, May 12, 2010 at 04:34:36PM +0930, Ian Holland wrote:
> Hi Eric
> It seems this has not fixed the problem. Does anyone have any other
> suggestions as to the possible cause? Note, I also found power cycling
> the USRP2 can sometimes avoid the same problem.
> Ian.


I still suspect something in your host setup.

Is the USRP2 connected directly to the host or does it go through a
switch?  If there's a switch in the path, please remove it.

Note that the cpu throttling / clock scaling hypothesis would explain
why it works better under higher load than lower load.  Are you sure
that your cpu isn't being throttled?

When you're seeing the problem, try:

  $ grep 'cpu MHz' /proc/cpuinfo

and see if all cores are running at full speed.


Idling laptop (throttled back from 1.83GHz):

  address@hidden ~]$ grep 'cpu MHz' /proc/cpuinfo
  cpu MHz               : 1000.000
  cpu MHz               : 1000.000

Server with cpu scaling disabled:

  address@hidden swig]$ grep 'cpu MHz' /proc/cpuinfo
  cpu MHz               : 2999.488
  cpu MHz               : 2999.488
  cpu MHz               : 2999.488
  cpu MHz               : 2999.488
  cpu MHz               : 2999.488
  cpu MHz               : 2999.488
  cpu MHz               : 2999.488
  cpu MHz               : 2999.488


> -----Original Message-----
> From: address@hidden
> [mailto:address@hidden On
> Behalf Of Ian Holland
> Sent: Tuesday, 11 May 2010 11:14 AM
> To: Eric Blossom
> Cc: address@hidden
> Subject: RE: [Discuss-gnuradio] Unexplained out-of-sequence packets...
> Thanks Eric
> I checked the power management preferences and couldn't see anything
> about CPU throttling, though I did verify it would never go to sleep
> after inactivity. Then, I found some info on
> http://blog.mpathirage.com/2009/10/04/how-to-disable-dynamic-frequency-s
> calingcpu-throttling-in-ubuntu-jaunty9-04/ to disable the CPU throttling
> (I know I am using 9.10, not 9.04, but I imagine it should be the same).
> After rebooting (only once), I haven't yet seen the problem again.
> Unfortunately, given the seemingly random nature of the problem, I guess
> it is a wait-and-see matter as to whether it ever does resurface.
> Cheers
> Ian.

reply via email to

[Prev in Thread] Current Thread [Next in Thread]