** Description changed: + Original Bug name: "panda: USB disk IO slow" + My Panda's USB seems to be significantly slower than a Beagle C4. hdparm shows buffered reads as ~12MB/s on the Panda, and about ~20-25MB/s on a Beagle C4 from the same external Lacie USB disk. Kernel is 2.6.37-1002-linaro-omap Disk shows as: [ 5.170440] scsi 0:0:0:0: Direct-Access LaCie d2 quadra PQ: 0 ANSI: 4 [ 5.172546] sd 0:0:0:0: Attached scsi generic sg0 type 0 [ 5.175415] sd 0:0:0:0: [sda] 976773168 512-byte logical blocks: (500 GB/465 GiB) The board is otherwise idle during the test. Doing perf_2.6.37-12 record -a dd if=/dev/sda of=/dev/null bs=4096 count=100000 shows : - 81.41% swapper [kernel.kallsyms] [k] default_idle - 6.33% dd [kernel.kallsyms] [k] __copy_to_user - 0.94% swapper [kernel.kallsyms] [k] cpu_idle - 0.51% dd [kernel.kallsyms] [k] __make_request - 0.51% perf_2.6.37-12 [kernel.kallsyms] [k] __copy_from_user - + 81.41% swapper [kernel.kallsyms] [k] default_idle + 6.33% dd [kernel.kallsyms] [k] __copy_to_user + 0.94% swapper [kernel.kallsyms] [k] cpu_idle + 0.51% dd [kernel.kallsyms] [k] __make_request + 0.51% perf_2.6.37-12 [kernel.kallsyms] [k] __copy_from_user which suggests it's not CPU constrained. Dave
** Summary changed: - panda: USB disk IO slow + ARM SMP scheduler performance bug -- 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: ARM SMP scheduler performance bug 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
