max latency

[Rui Araujo]

Source package: linux-rt
1) The release of Ubuntu you are using
$ lsb_release -rd
Description: Ubuntu 9.04
Release: 9.04
$ cat /proc/cpuinfo
...
model name : Intel(R) Core(TM)2 Duo CPU T9400 @ 2.53GHz2)
...
2) The version of the package you are using:
$ apt-cache policy linux-rt
linux-rt:
  Installed: 2.6.28.3.1
  Candidate: 2.6.28.3.1
  Version table:
 *** 2.6.28.3.1 0
        500 http://archive.ubuntu.com jaunty/multiverse Packages
        100 /var/lib/dpkg/status
3) What you expected to happen:
using the cyclictest program (http://rt.wiki.kernel.org/index.php/Cyclictest) with load stressed machine obtain a maximum latency of a few tens (say 10 to 50) of microseconds at most.
4) What happened instead:
# ./cyclictest -a -t -n -p99
policy: fifo: loadavg: 2.49 2.19 0.95 1/360 6527

T: 0 ( 5779) P:99 I:1000 C: 154377 Min: 1 Act: 3 Avg: 5 Max: 21673
T: 1 ( 5780) P:98 I:1500 C: 102918 Min: 1 Act: 4 Avg: 5 Max: 21137
# uname -a
Linux batel 2.6.28-3-rt #12-Ubuntu SMP PREEMPT RT Fri Apr 17 10:09:12 UTC 2009 x86_64 GNU/Linux

[Alessio Igor Bogani (abogani)]

Thank you for taking the time to report this bug and helping to make Ubuntu better. The issue that you reported is one that could be fixed in the Beta release of Karmic Koala. It would help us greatly if you could test with it! Thanks again and we appreciate your help.

[Rui Araujo (rui)]

I would be happy to collaborate in testing with the kernel version undergoing debugging of this bug. The PC that I have access for testing and where I have seen this bug is my laptop that I continuously use for work. I would like to upgrade to Ubuntu 9.10 final release. As soon as final 9.10 is released, I must then find a time window where I will be
comfortable to update / install 9.10 without affecting normal work. I feel I could participate in 9.10 beta testing still using the 9.04 setup but installing and testing only the 9.10 linux-rt kernel under debug. Is it possible? How could that be done / implemented? What do you think about this?

[Alessio Igor Bogani (abogani)]

Rui Araujo,

It could be possible (test Karmic kernel on Jaunty) but I don't suggest it to you if this system is your primary one.
So please provide feedback as soon as possible when you'll switch that system on Karmic.

Thanks!

[Alessio Igor Bogani (abogani)]

We are closing this bug report because it lacks the information we need to investigate the problem. Please reopen it if you can give us the missing information, and don't hesitate to submit bug reports in the future. To reopen the bug report you can click on the current status, under the Status column, and change the Status back to "New". Thanks again!