On Mon, 1 Aug 2011, Michael Sparmann wrote: > No noticable improvement: http://paste.ubuntu.com/656498/
The nohlt argument prevents the idle power saving code from being called at all. So if that doesn't help the USB case either than it is unlikely that anything related to sleep modes. -- You received this bug notification because you are a member of Linaro Release Team, which is subscribed to the bug report. https://bugs.launchpad.net/bugs/709245 Title: panda: USB disk IO slow Status in Linaro Ubuntu Evaluation Builds: Confirmed Status in Linaro Linux: Confirmed Status in “linux-ti-omap4” package in Ubuntu: Confirmed Status in “linux-ti-omap4” source package in Oneiric: Confirmed Bug description: 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 which suggests it's not CPU constrained. Dave To manage notifications about this bug go to: https://bugs.launchpad.net/linaro-ubuntu/+bug/709245/+subscriptions _______________________________________________ Mailing list: https://launchpad.net/~linaro-release Post to : [email protected] Unsubscribe : https://launchpad.net/~linaro-release More help : https://help.launchpad.net/ListHelp
