linaro-pkg team mailing list archive

[Emeric Vigier <709245@xxxxxxxxxxxxxxxxxx>]

1. Here I booted Android without RJ45 cable plugged. I issued:
# cat /sys/kernel/debug/usb/usbmon/1u > /sdcard/1.mon.out.11

2. Then I plugged in the cable, got an IP address through DHCP:
(panda) # netcfg eth0 dhcp
eth0     UP                              192.168.50.107/24  0x00001043 42:82:7e:fd:d9:71

3. Then I started a TX using nc command:
(panda) # nc -l -p 1032 < /dev/zero &
(desktop-pc) $ nc 192.168.50.107 1032 > /dev/null
(desktop-pc) $ sudo nethogs
nc     eth0   0.486      12.532 KB/sec
Speed is very poor.

4. I wait for netdev watchdog to bark and stopped the nc on desktop-pc
side. Then killed the nc on panda side. And eventually ctrl'ed-C the
usbmon dump.

On my dmesg, you can see the slow path occurring after TX struggled for a while:
http://paste.ubuntu.com/1083276/

The usbmon trace on bus 1:
http://paste.ubuntu.com/1083284/

My usb connected devices:
http://paste.ubuntu.com/1083292/

Thanks for your kind support,
Emeric

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Maintainers, which is the registrant for Linaro Linux.
https://bugs.launchpad.net/bugs/709245

Title:
  ARM SMP scheduler performance bug

Status in Linaro Ubuntu Evaluation Builds:
  Fix Released
Status in Linaro Linux:
  Fix Committed
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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