Red Hat Bugzilla – Bug 80819
Kernel is not handling multiple tasks correctly (not sure its a task problem)
Last modified: 2008-01-17 12:49:42 EST
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Description of problem:
When i copy files from a cd-rom for example all the system gets slow
(maybe an ext3 problem ?). I ran the command top (several times) to see the cpu
utilization and the maximum was 20%. I copied the files with both nautilus and
the command cp and both gives me the same result, everything gets slow. By slow
i mean *very* slow.
Athlon 1.2Ghz 256mb ram
52x creative cd-rom
Hd maxtor 40gb ata 133 (my board is ATA 100)
Version-Release number of selected component (if applicable):
Steps to Reproduce:
1. Copy files from a not-so-fast media to the root partition.
2. The system will be ***VERY*** slow during the copy.
Check to see if your cdrom is using DMA with hdparm -d device RedHat has made
it policy to disable DMA on cdrom drives for compatiability reasons. Which has
the effect of greatly slowing it down for everyone else.
[root@zeus sayao]# /sbin/hdparm -d /dev/cdrom
using_dma = 1 (on)
During the boot kernel shows this message:
my cd-rom is /dev/hda
The only way that I have found to reliably switch CD-ROM drives to DMA Mode is to:
su to root
cp harddisks harddiskhda (or harddiskhdb or whatever your CD-ROM is.)
edit the newly created harddiskhda with a text editor and change the USE_DMA=0
save the file and restart the machine.
Thanks for the bug report. However, Red Hat no longer maintains this version of
the product. Please upgrade to the latest version and open a new bug if the problem
The Fedora Legacy project (http://fedoralegacy.org/) maintains some older releases,
and if you believe this bug is interesting to them, please report the problem in
the bug tracker at: http://bugzilla.fedora.us/