I tested some more today (Oneiric 3.0 kernel) and the external USB drive on a Panda.
With nosmp passed on the boot command line, the throughput is good with or without the ping and about the same as using both cores and pinging it. Booting with both cores and putting cpu1 offline does not seem to affect the behaviour - pinging leads to 4x or 5x throughput over not-pinging. So it may be related to SMP scheduling. Also nosmp and putting one core offline at runtime is apparently not the same ( I naively thought it should be) -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/709245 Title: panda: USB disk IO slow To manage notifications about this bug go to: https://bugs.launchpad.net/linaro-ubuntu/+bug/709245/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
