Red Hat Bugzilla – Bug 126781
ServerWorks CNB20HE/OSB4 IDE Controller - poor performance
Last modified: 2007-11-30 17:10:45 EST
The problem is very poor IDE performance of a Seagate (hda: ST360021A,
ATA DISK drive) which is attached to an onboard ServerWorks CNB20HE
chipset to primary 'OSB4' IDE controller.
`hdparm -Tt /dev/hda' returns 286.90 MB/s and _only_ 10.25 MB/sec,
which is about 4 times slower than what this hdd could perform.
DMA is enabled in the BIOS and it works (as hdparm and dmesg say).
Version-Release number of selected component (if applicable):
Steps to Reproduce:
1.attach IDE drive to any SW OSB4 IDE controller
2.format hdd as ext2
3.hdparm -t /dev/hda returns only ~10MB/s
Expected Results: hdparm -t should return ~40MB/s, not ~10MB/s
DMA is enabled, filesystem is ext2, CPU is 1000MHz PIII.
### hdparm /dev/hda
multcount = 16 (on)
IO_support = 0 (default 16-bit)
unmaskirq = 0 (off)
using_dma = 1 (on)
keepsettings = 0 (off)
readonly = 0 (off)
readahead = 256 (on)
geometry = 65535/16/63, sectors = 117231408, start = 0
I tried changing controllers, cables and all BIOS settings.
Kernel is recompiled from kernel-2.6.6-1.422.src.rpm, the same thing
was happening on whole range of 2.4.x kernels, 2.6 kernel fixed the
problem of CRC errors on that controller, but poor performance stayed.
Ultra-DMA is not supported on the OSB4 controller because of problems
with the chip occasionally corrupting transfers in UDMA modes with
Later CSB5/CSB6 devices are supported with full UDMA.
If you have two controllers it is best to have CD/DVD devices on the
OSB4 (which will do UDMA with these devices) and the disk on the
Created attachment 101438 [details]
dmesg from 2.6.6-1.422custom
# ATA/ATAPI/MFM/RLL support
# Please see Documentation/ide.txt for help/info on IDE drives
# CONFIG_BLK_DEV_HD_IDE is not set
# IDE chipset support/bugfixes