3-4MB/s vinum performance with two Promise PDC20268 UDMA100 controllers

[jason]

Bjorn Eikeland wrote:

> Hi
>
> I had four 160G IDE drives in raid5 on a single controller and it 
> worked just fine, never benchmarked it since it was faster than the 
> network anyway. But when adding a second controller card and two more 
> drives the new array has a terrible write performance.
>
> I've tried various stripe and block sizes in desperation but that 
> didnt help. Then I've tried assinging the same irq to both controller 
> card in case it was interrupts causing the slow down, so I set both 
> pci slots to use irq3 in the bios (freebsd wants irq 3 for a non 
> existent sio1 port - so I figure that'll be 'free'?) but despite my 
> setting in the bios the cards still show up in dmesg with irq 21 and 22?
>
> So I looked thourgh the handbook and tried setting the irq in 
> /boot/device.hints both as  hint.atapci.x.irq="3" and 
> hint.ata.x.irq="3" but this didnt work either.
>
> The problem is the same in freebsd 5.1 and 5.2 (output below is form 
> 5.2):
>
> home# dmesg | grep atapci
> atapci0: <Promise PDC20268 UDMA100 controller> port 
> 0xb000-0xb00f,0xb400-0xb403,0xb800-0xb807,0xd000-0xd003,0xd400-0xd407 
> mem 0xf9000000-0xf9003fff irq 21 at device 9.0 on pci1
> atapci0: [MPSAFE]
> ata2: at 0xd400 on atapci0
> ata3: at 0xb800 on atapci0
> atapci1: <Promise PDC20268 UDMA100 controller> port 
> 0x9400-0x940f,0x9800-0x9803,0xa000-0xa007,0xa400-0xa403,0xa800-0xa807 
> mem 0xf8800000-0xf8803fff irq 22 at device 10.0 on pci1
> atapci1: [MPSAFE]
> ata4: at 0xa800 on atapci1
> ata5: at 0xa000 on atapci1
> atapci2: <Intel ICH2 UDMA100 controller> port 0x8800-0x880f at device 
> 31.1 on pci0
> ata0: at 0x1f0 irq 14 on atapci2
> ata1: at 0x170 irq 15 on atapci2
>
> Any thoughts anyone?
>
> Bjorn
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Don't assign the same irq to 2 devices, thats a conflict!  You may not 
have used win95, but you don't won't to do that.  I know raid 5 isslower 
than raid 1, but I don't remember any numbers.  Also the more complex 
you make the system the slower it will go, hince raid 5 slower than raid 
1.  Also pci is a shared bus meaning 1 device talks at a time, so maybe, 
just maybe if you chipset has a pci bridge because you have like 8 
slots, or the make was real kind, you could try card 1 in say slot 2, 
and card 2 in slot 6?  You maybe able to get simultainsuos writes and 
reads that way.  The best option is pcix, or a controler that support 8 
drives on its own.  Also try to adjust pci latincy or waiting, do a 
google on it, I hear 95-128 clicks is good.  I just noticed the buillt 
in ide is on pci0 while the rest are on pci1, theres a bridge you can 
use.  If you can get it setup, have 2 drives connected to the onboard 
ide and the rest to your card.
Jason