[Linux-usb-users] USB HDD "works" but locks machine until finished transfer

[Ian David Flintoft]

Hello,

I've just got a Lacie Pocket Drive USB 2.0 40 Gb HDD.
At the moment I've tried using the HDD only with USB1.1
controllers.

The disk is basically working however when I use it with
an ext2 filesystem mounted asynchronously it locks the machine hard until the transfer is finished for data
transfers greater than a few 100 Mb's. If I mount
the partition with the sync option then it seems to
work reliably but at a very low rate - which isn't much
fun with a 40 GB HDD.
The problem gets worse the larger the amount of data
written. With about 312 MB on a system with 256MB of RAM
a large portion is written to buffers quickly and then
once it starts to commit to the disk there are a few minor latency problems but nothing too serious.
With a large copy (e.g. 2 Gb) once the buffers start to
be written to disk the system very quickly locks up
completely until the transfer is finished and the
effective data rate goes through the floor ( < 14 kb/s).
Although I'm no expert on kernels it "feels" like some
kind of deadlock/race, maybe in the ext2 fs or block layer - possibly due to the very low rate available over USB1.1
for such large transfers breaking some assumptions. Nothing in the logs.

Using a vfat filesystem the problem seems to be better,
certainly with moderate size transfer I get a reasonable
rate and no significant latency issues. I haven't had time
to try a 2Gb copy yet. Unfortunately vfat doesn't support
symbolic links and screws around with filename cases so
it is not well suited for keeping a debain archive on, for
example.

I have seen something similar before with old parallel port
zip disk on early 2.4 kernels using certain transfer modes
which would also lock the system until finished and take about
an hour to write 100 Mb.

I haven't had time to play with other kernels yet so maybe
that is worth a try. I'll also try the verbose debugging options in the USB system.

Anyone got any ideas or seen anything similar?
Details of system and performance observed below.
Similar things happen on two other machines - a dual AMD AthlonMP, 512Mb using ohci and a Pentium II, 512Mb with uhci.


Performance
-----------

File system on sda1 made with

mke2fs /dev/sda1

or

mkfs.vfat -F 32 /dev/sda1

Write 312MB of files (cp -a), check md5sums of files (md5sum -c ./md5sum.txt) and then delete all files (rm -rf).

fs opts -------------------------------------------------------------------------
ext2 sync write 312MB 36m30s 142kB/s OK
delete 312MB 0m38s - OK

vfat write 312MB 7m25s 701kB/s OK
md5sum 7m23s 704kB/s OK
delete 312MB 0m05s - OK

ext2 async write 312MB 7m14s 719kB/s OKish minor latency issues
md5sum 7m01s 741kB/s OK
delete 312MB 0m04s - OK

ext2 async write 2100MB 65m to write 65Mb 16 kb/s
Gave up (= reset button) after 65Mb before giving up.
e2fsck fixed a few broken inodes etc on reboot.
md5sums on what was written (after e2fsck) are OK
Appears to be working but very very slowly and blocks all opther processes?

(time includes time to umount device and sync buffers)



Hardware
========

Dell Inspiron 4100
Intel Pentium III 1GHz
256 Mb SDRAM
(512 Mb swap)


OS
==

Debian GNU/Linux 3.0 + all security update to 4/11/02
KDE 3.0.3 self install

linux 2.4.20-rc1
alsa 0.9r5

hotplug 20020114
usbview 1.0
usbutils 0.9
modutils 2.4.15


Relevant Modules
================

nls_iso8859-1 2848 0 (autoclean)
nls_cp437 4384 0 (autoclean)
vfat 9308 0 (autoclean)
fat 29240 0 (autoclean) [vfat]
sd_mod 9916 2 (autoclean)
vmnet 18464 3
parport_pc 13892 0
parport 24576 0 [parport_pc]
vmmon 19444 0 (unused)
ds 6464 2
irtty 7200 2 (autoclean)
irda 138476 1 (autoclean) [irtty]
usb-storage 54208 1
scsi_mod 51868 2 [sd_mod usb-storage]
usb-uhci 21220 0 (unused)


USB Root Hub
============

USB 1.1

usbview
-------

USB UHCI Root Hub
Serial Number: bf80
Speed: 12Mb/s (full)
Number of Ports: 2
Bandwidth allocated: 0 / 900 (0%)
Total number of interrupt requests: 0
Total number of isochronous requests: 0
USB Version: 1.00
Device Class: 09(hub )
Device Subclass: 00
Device Protocol: 00
Maximum Default Endpoint Size: 8
Number of Configurations: 1

Config Number: 1
Number of Interfaces: 1
Attributes: 40
MaxPower Needed: 0mA

Interface Number: 0
Name: hub
Alternate Number: 0
Class: 09(hub )
Sub Class: 0
Protocol: 0
Number of Endpoints: 1

Endpoint Address: 81
Direction: in
Attribute: 3
Type: Int.
Max Packet Size: 8
Interval: 255ms

USB Device
==========

Lacie Pocketdrive 40 Gb

USB 2.0


usbview
-------

LaCie PocketDrive USB2
Manufacturer: LaCie
Serial Number: 11100E00050EE6EC
Speed: 12Mb/s (full)
USB Version: 2.00
Device Class: 00(>ifc )
Device Subclass: 00
Device Protocol: 00
Maximum Default Endpoint Size: 64
Number of Configurations: 1
Vendor Id: 059f
Product Id: 0211
Revision Number: 11.06

Config Number: 2
Number of Interfaces: 1
Attributes: c0
MaxPower Needed: 98mA

Interface Number: 0
Name: usb-storage
Alternate Number: 0
Class: 08(stor.)
Sub Class: 6
Protocol: 50
Number of Endpoints: 3

Endpoint Address: 01
Direction: out
Attribute: 2
Type: Bulk
Max Packet Size: 64
Interval: 0ms

Endpoint Address: 82
Direction: in
Attribute: 2
Type: Bulk
Max Packet Size: 64
Interval: 0ms

Endpoint Address: 83
Direction: in
Attribute: 3
Type: Int.
Max Packet Size: 2
Interval: 32ms

Interval: 32ms

Disk
====

Disk /dev/sda: 255 heads, 63 sectors, 4864 cylinders
Units = cylinders of 16065 * 512 bytes

Device Boot Start End Blocks Id System
/dev/sda1 1 1020 8193118+ 83 Linux
/dev/sda2 1021 1785 6144862+ 83 Linux
/dev/sda3 1786 4864 24732067+ 5 Extended
/dev/sda5 1786 2298 4120641 c Win95 FAT32 (LBA)
/dev/sda6 2299 2811 4120641 83 Linux
/dev/sda7 2812 3324 4120641 83 Linux
/dev/sda8 3325 3837 4120641 83 Linux
/dev/sda9 3838 4350 4120641 83 Linux
/dev/sda10 4351 4864 4128673+ 83 Linux


--

Dr Ian David Flintoft Email: [EMAIL PROTECTED] Applied Electromagnetics Group Tel: +44 (0) 1904 432391
Department of Electronics Fax: +44 (0) 1904 433224 University of York Heslington YORK, UK YO10 5DD



-------------------------------------------------------
This sf.net email is sponsored by: See the NEW Palm Tungsten T handheld. Power & Color in a compact size!
http://ads.sourceforge.net/cgi-bin/redirect.pl?palm0001en
_______________________________________________
[EMAIL PROTECTED]
To unsubscribe, use the last form field at:
https://lists.sourceforge.net/lists/listinfo/linux-usb-users