On Wed, Jan 09, 2013 at 11:53:25AM +0000, t [dot] t [dot] g [dot] clephas [..] ... wrote:
> Hi all,
>
> We have one (critical) PC were the period cannot be set below 0.004.
> Any values below this are ignored.
>
> We can reproduce this using the below example:
>
>
> 1 import("rtt_ros_integration_example")
> 2 import("rtt_std_msgs")
> 3
> 4 # Load a HelloRobot component
> 5 loadComponent("HelloRobot","HelloRobot")
> 6
> 7 # Give it a periodic activity
> 8 setActivity("HelloRobot",0.001,HighestPriority,ORO_SCHED_RT)
> 9
> 10 # Create connections
> 11 stream("HelloRobot.float_out", ros.topic("float_out"))
> 12 stream("HelloRobot.float_in", ros.topic("float_in"))
> 13 stream("HelloRobot.string_out", ros.topic("string_out"))
> 14 stream("HelloRobot.string_in", ros.topic("string_in"))
> 15
> 16 # Configure the HelloRobot component
> 17 HelloRobot.configure()
> 18
> 19 # Start it
> 20 HelloRobot.start()
>
>
> And we listen to the port on ros using: rostopic hz /float_out
>
> It gives us a frequency of 250 hz. All values for Ts higher than 0.004
> display the correct frequency.
>
> PC configuration:
> Ubuntu 12.04 server edition. ROS fuerte, latest version of all debian
> packages. (orocos_toolchain also installed with apt-get)
>
> No other PC's in our lab suffered from this condition. (not even one
> identical PC)
>
> The PC has had a fresh installation with the same configuration and now
> everything works.
> This means we cannot reproduce the error anymore, has anyone had similar
> issues?

The symptoms remind me of the behavior of old pre- NO_HZ, pre-
HIGH_RES_TIMERS systems, but that seems unlikely given your recent
distribution, unless you've compiled you own kernel...

Markus