2002-02-12 11:43:56

by Martin Josefsson

[permalink] [raw]
Subject: Question about i820 chipset.

Hi Alan,

I have some small questions...

Have you ever tried a motherboard with i820 chipset and two NIC's?
I have a Asus P3C-D here (dual pIII 800 with 256MB rimm) and a D-Link
DFE570-TX NIC (quad DECchip 21143 behind a DECchip 21152 pci bridge).

The problem I'm seeing is extremely crappy pci performance.
With one of the NIC's active I see no real problems but when two NIC's are
active at the same time all hell breaks loose :(

if I generate traffic out via 2 NIC's at the same time I'd expect to get
about 2 x 100Mbit/s but in reality I get 2 x 25Mbit/s with this
motherboard. and with 3 NIC's active I get about 3 x 15-20Mbit/s.

I tried replacing the motherboard with an old SMP board based on the 440bx
chipset (cpus underclocked to 600MHz) and then I can easily get 3 x
100Mbit/s with 25-30% cpu used in the machine.

So my question is, have you ever seen such pci issues? I've tried all
BIOS settings I could find and a lot of diffrent kernels. I've also tried
the vanilla tulip-driver and the NAPI'fied one (which I have been helping
to test) and both show the exact same performanceproblems.

I tried routing a lot of packets and it started dropping a lot of packets
when the cpu was only 75% used according to both vmstat and cyclesoak
(with an UP kernel). A profile shows that default_idle gets about 25% of
the time. I assume the kernel is waiting for the pci bus.

And the last question, if you have the hardware, would you mind testing
something similar on the Asus A7M266-D? We've been thinking of getting a
few of these boards to replace the crappy i820 ones.

I saw that you included a patch for MPS 1.4 in -pre9-ac1, was this the
same patch you were talking about earlier and does it work?

/Martin

Never argue with an idiot. They drag you down to their level, then beat you with experience.



2002-02-12 12:23:54

by Davidovac Zoran

[permalink] [raw]
Subject: Re: Question about i820 chipset.

try to change slot
perhaps one of your nic is sharing irq with mouse usb ide
etc so change slot
check with more /proc/interrupts

On Tue, 12 Feb 2002, Martin Josefsson wrote:

> Hi Alan,
>
> I have some small questions...
>
> Have you ever tried a motherboard with i820 chipset and two NIC's?
> I have a Asus P3C-D here (dual pIII 800 with 256MB rimm) and a D-Link
> DFE570-TX NIC (quad DECchip 21143 behind a DECchip 21152 pci bridge).
>
> The problem I'm seeing is extremely crappy pci performance.
> With one of the NIC's active I see no real problems but when two NIC's are
> active at the same time all hell breaks loose :(
>
> if I generate traffic out via 2 NIC's at the same time I'd expect to get
> about 2 x 100Mbit/s but in reality I get 2 x 25Mbit/s with this
> motherboard. and with 3 NIC's active I get about 3 x 15-20Mbit/s.
>
> I tried replacing the motherboard with an old SMP board based on the 440bx
> chipset (cpus underclocked to 600MHz) and then I can easily get 3 x
> 100Mbit/s with 25-30% cpu used in the machine.
>
> So my question is, have you ever seen such pci issues? I've tried all
> BIOS settings I could find and a lot of diffrent kernels. I've also tried
> the vanilla tulip-driver and the NAPI'fied one (which I have been helping
> to test) and both show the exact same performanceproblems.
>
> I tried routing a lot of packets and it started dropping a lot of packets
> when the cpu was only 75% used according to both vmstat and cyclesoak
> (with an UP kernel). A profile shows that default_idle gets about 25% of
> the time. I assume the kernel is waiting for the pci bus.
>
> And the last question, if you have the hardware, would you mind testing
> something similar on the Asus A7M266-D? We've been thinking of getting a
> few of these boards to replace the crappy i820 ones.
>
> I saw that you included a patch for MPS 1.4 in -pre9-ac1, was this the
> same patch you were talking about earlier and does it work?
>
> /Martin
>
> Never argue with an idiot. They drag you down to their level, then beat you with experience.
>
>
> -
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to [email protected]
> More majordomo info at http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at http://www.tux.org/lkml/
>

2002-02-12 12:48:46

by Martin Josefsson

[permalink] [raw]
Subject: Re: Question about i820 chipset.

On Tue, 12 Feb 2002, Davidovac Zoran wrote:

> try to change slot
> perhaps one of your nic is sharing irq with mouse usb ide
> etc so change slot
> check with more /proc/interrupts

Using an UP kernel with IO-APIC support and MPS 1.4 they don't share irqs:

CPU0
0: 66083638 IO-APIC-edge timer
1: 828 IO-APIC-edge keyboard
2: 0 XT-PIC cascade
4: 3 IO-APIC-edge serial
8: 0 IO-APIC-edge rtc
14: 17840 IO-APIC-edge ide0
16: 14 IO-APIC-level eth2
17: 12 IO-APIC-level eth3
18: 20790 IO-APIC-level eth0
19: 39 IO-APIC-level eth1
NMI: 66083576
LOC: 66081746
ERR: 0
MIS: 0

I've tried changing slots aswell and I havn't seen any improvments with
either MPS 1.1 or 1.4

/Martin

Never argue with an idiot. They drag you down to their level, then beat you with experience.

2002-02-12 13:37:31

by Davidovac Zoran

[permalink] [raw]
Subject: Re: Question about i820 chipset.



> Using an UP kernel with IO-APIC support and MPS 1.4 they don't share irqs:

try without IO-APIC support is it still the same ?

Z
>
> CPU0
> 0: 66083638 IO-APIC-edge timer
> 1: 828 IO-APIC-edge keyboard
> 2: 0 XT-PIC cascade
> 4: 3 IO-APIC-edge serial
> 8: 0 IO-APIC-edge rtc
> 14: 17840 IO-APIC-edge ide0
> 16: 14 IO-APIC-level eth2
> 17: 12 IO-APIC-level eth3
> 18: 20790 IO-APIC-level eth0
> 19: 39 IO-APIC-level eth1
> NMI: 66083576
> LOC: 66081746
> ERR: 0
> MIS: 0
>
> I've tried changing slots aswell and I havn't seen any improvments with
> either MPS 1.1 or 1.4
>
> /Martin
>
> Never argue with an idiot. They drag you down to their level, then beat you with experience.
>
> -
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to [email protected]
> More majordomo info at http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at http://www.tux.org/lkml/
>

2002-02-12 13:55:14

by Martin Josefsson

[permalink] [raw]
Subject: Re: Question about i820 chipset.

On Tue, 12 Feb 2002, Davidovac Zoran wrote:

>
>
> > Using an UP kernel with IO-APIC support and MPS 1.4 they don't share irqs:
>
> try without IO-APIC support is it still the same ?

IIRC I've tried that too without any success :(

/Martin

Never argue with an idiot. They drag you down to their level, then beat you with experience.