Bug 189247 - external usb 2.0 disk slow in reading
Summary: external usb 2.0 disk slow in reading
Keywords:
Status: CLOSED CURRENTRELEASE
Alias: None
Product: Fedora
Classification: Fedora
Component: kernel
Version: 5
Hardware: athlon
OS: Linux
medium
high
Target Milestone: ---
Assignee: Kernel Maintainer List
QA Contact: Brian Brock
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2006-04-18 15:39 UTC by Frank-Michael Fischer
Modified: 2007-11-30 22:11 UTC (History)
1 user (show)

Fixed In Version: 2.6.16-1.2096_FC5
Doc Type: Bug Fix
Doc Text:
Clone Of:
Environment:
Last Closed: 2006-04-22 13:20:25 UTC
Type: ---
Embargoed:


Attachments (Terms of Use)

Description Frank-Michael Fischer 2006-04-18 15:39:57 UTC
Description of problem: My external USB 2.0 disk normally running at about
20MB/s when writing and 25MB/s when reading on any other Linux system (Ubuntu,
Knoppix, SUSE) reads only at about 12MB/s when reading under FC5. Writing is ok.
The speed reduction does not depend on the filesystem in use (tested with vfat,
ext3 and xfs)


Version-Release number of selected component (if applicable): udev 084-13,
kernel 2.6.16-1.2080_FC5 i686


How reproducible: disconnect and reconnect the disk, then use:

dd if=/media//PORTY/mifi/test.dat of=/dev/null

or

time cp /media/PORTY/mifi/test.dat /dev/null

  
Actual results: 1073741824 bytes (1.1 GB) copied, 88.8305 seconds, 12.1 MB/s


Expected results: 1073741824 bytes (1.1 GB) copied, 50.8846 seconds, 21.1 MB/s


Additional info: changing the "dd" blocksize to some value between 512 and 8M
does not effect the reading speed.

Comment 1 Frank-Michael Fischer 2006-04-22 13:20:25 UTC
Problem gone with kernel 2.6.16-1.2096_FC5


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