Performance loss running 2.4 kernel

[gianfranko]

I just installed kernel 2.4 on my Mandrake 7.2 distro. At first, I noticed that the computer was running considerably slower. So I went to the console and ran hdparm
first I ran the hdparm -k1 -c1 -d1 /dev/hda
then I ran hdparm -t /dev/hda this gave me an output of 12.8mb/s , this number confirmed what I suspected. Under the 2.2 kernel hdparm -t /dev/hda gave me an output of 18mb/s I also noticed lack of performance on my scsi drives one of them went from 28mb/s under the 2.2kernel to 18mb/s in 2.4.

Could it be that I forgot to turn some option to "y" while running make xconfig? Because I have no idea as to which one could it be...
any thoughts?

[CMonster]

I have upgraded two Mandrake 7.2 systems to 2.4 kernel, and though the drive speed was the same as 2.2 kernel, there was a noticable improvement in overall speed in both systems. You must have misconfigured something.

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CMonster says, "You can't choose the right OS if you don't have a choice."

[This message has been edited by CMonster (edited 16 January 2001).]

[Luthor]

I saw similar results when I left out a few options under "ATA/IDE/MFM/RLL Support" -> "IDE, ATA, and ATAPI Block devices" a while back.

Check the following:
"Use PCI DMA by default when available"

and, if you have Intel PIIXn chipset:
"Intel PIIXn chipset support" which allows you to select, "PIIXn Tuning support"

This allows for the following.

Make sure you enable 32-bit access and DMA support (do this at your own risk).

hdparm -c3 -d1 /dev/<yourdisk>

-d1 enables DMA transfers and -c3 sets 32-bit disk access.

Try "hdparm -tT /dev/<yourdisk> before and after to check results.

I included the commands (not the test) in my rc.local file to insure they are done each restart. I noticed an immediate improvement.

Hope this helps...



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Luthor St. James
(aka [AcK]BillTheCat)

[gianfranko]

Is is there any difference between
hdparm -c1 and hdparm -c3 both enable 32bit disk access correct?

[gianfranko]

"Intel PIIXn chipset" Is that only for Pentium2 machines or will it also work on my Pentium3 machine?

[Luthor]

I am sure the PIIXn chipset supports PIII so if your Motherboard uses that chipset, you are OK enabling that option.




------------------
Luthor St. James
(aka [AcK]BillTheCat)

[CMonster]

gianfranco - I have now noticed a similar problem with a VIA 82C586 chipset/ CeleronII system and am researching it now. BTW, how did you check the SCSI drives?

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CMonster says, "You can't choose the right OS if you don't have a choice."

[gianfranko]

Cmonster: I tested the scsi drive using hdparm also, the command was:

hdparm -t /dev/sda

this also showed a terrible drop of performance

I'll try enabling the PII chipset thingy and get back to you with my results

[gianfranko]

I enabled the PIIXn chipset support but not much of an improvement: hdparm -t /dev/hda
gives the output of 12.9mb/s

It must be something else...

anyone out there has any ideas?

[mindwarp]

Drake 7.2 here with some other damn hdparm problem.. unfortunately I cant remember what the exact message was.. I believe it wouldnt let me turn on either 32-bit or dma.. possibly I missed something while configin.. I will try again and post results

Mindwarp