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Re: ATA-100 disk under 2.2.18 -- horrible performance



On 07 Jan 2001 03:58:45 -0500, Arcady Genkin said:

> I have an IBM ATA-100 30G harddrive, attached to a ASUS CUSL2-C (Intel
>  815EP-based) mobo.
>  
>  The kernel is not even using the drive in UDMA mode.  The performance
>  is *horrible*: every time I copy to the disk the CPU usage goes up all
>  the way and I'm seeing things like "load average: 5.47, 5.02, 3.27",
>  which is only caused by disk access.
>  
>  ,----[ dmesg ]
>  | PCI_IDE: unknown IDE controller on PCI bus 00 device f9, VID=8086, DID=244b
>  | PCI_IDE: not 100% native mode: will probe irqs later
>  |     ide0: BM-DMA at 0xa800-0xa807, BIOS settings: hda:DMA, hdb:pio
>  |     ide1: BM-DMA at 0xa808-0xa80f, BIOS settings: hdc:DMA, hdd:pio
>  | hda: QUANTUM FIREBALLP LM10.2, ATA DISK drive
>  | hdc: IBM-DTLA-307030, ATA DISK drive
>  | ide0 at 0x1f0-0x1f7,0x3f6 on irq 14
>  | ide1 at 0x170-0x177,0x376 on irq 15
>  | hda: QUANTUM FIREBALLP LM10.2, 9797MB w/1900kB Cache, CHS=19906/16/63, UDMA
>  | hdc: IBM-DTLA-307030, 29314MB w/1916kB Cache, CHS=59560/16/63
>  `----
>  As you can see, the other HD (which is an ATA-66 Quantum) is at least
>  used in UDMA mode.
>  
>  What is the reason the kernel dislikes the drive so much? ;^)
>  Do you suppose I've missed some option in kernel configuration?  Any
>  other possible reasons?  Could the fact that the whole drive is one
>  30G ext2fs partition have anything to do with the slowness?
> 
	Well i am using the identical ibm drive on an abit mb without
ATA100 support. In my kernel config i  set IDEDMA_AUTO=y so the
kernel automatically enables DMA.
	When i run hdparm  -i  it shows:
 UDMA modes: mode0 mode1 mode2 mode3 *mode4 mode5 
	And hdparm -t shows disk reads about 30MB/sec.
	Maybe you have to manually enable DMA for this drive.



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