** Changed in: linux-linaro
Status: Fix Committed => Fix Released
** Changed in: linux-linaro
Assignee: Mian Yousaf Kaukab (mian-yousaf-kaukab) => (unassigned)
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https://bugs.launchpad.net/bugs/709245
Title:
ARM SMP scheduler performance bug
Status in Linaro Ubuntu Engineering Builds:
Fix Released
Status in Linaro Linux:
Fix Released
Status in OEM Priority Project:
Fix Released
Status in OEM Priority Project maverick series:
Fix Released
Status in OEM Priority Project natty series:
Fix Released
Status in OEM Priority Project oneiric series:
Fix Released
Status in “linux-ti-omap4” package in Ubuntu:
Fix Released
Status in “linux-ti-omap4” source package in Maverick:
Fix Released
Status in “linux-ti-omap4” source package in Natty:
Fix Released
Status in “linux-ti-omap4” source package in Oneiric:
Fix Released
Bug description:
Original Bug name: "panda: USB disk IO slow"
This bug effects ARM Cortex A9 cores, snowball, nvidia, OMAP 4, and
other Cortex A9 processors. Problem is in Fedora ARM builds also so
not limited to Ubuntu.
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
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