ATA activity under SMP affecting USB interrupts? (Was Re: usb scheduling overruns under system load)

Hello again,

I've been doing some additional testing. It appears that the scheduling
overrun errors printed from ohci.c:1192 only seem to happen under
moderate/high disk load. I've noticed that the message gets printed out
under the following conditions:

- (un)bzip2'ing, (un)gzip'ing larger files (20MB+).
- cvsup'ing ports or system sources.
- moving large files between disks.
- compiling world and building a port.
- large ftp file transfers over the local network.

Everything in this list seems to involve disk activity. Unless there's
something that I'm missing, is it fair to assume that there's something
possibly in ATA-land which is affecting/delaying USB interrupt delivery?

The disks in this system are identical Maxtor 200GB drives with 8MB cache,
each connected to a seperate channel on the bundled Maxtor ATA133 card.

ad4: 194481MB <Maxtor 6Y200P0> [395136/16/63] at ata2-master UDMA133
ad6: 194481MB <Maxtor 6Y200P0> [395136/16/63] at ata3-master UDMA133

I've made the output of 'pciconf -vl' available at:
http://siliconlandmark.com/staff/andre/files/BLING.pciconf

In order to narrow down the list of possible causes, I installed to dnetc
port to see if CPU load would cause the message to be printed out. I then
proceeded to disable ACPI, but that didn't help any.

I guess I'll copy freebsd-smp_at_ on this one...

Any ideas?

> Andre Guibert de Bruet | Enterprise Software Consultant >
> Silicon Landmark, LLC. | http://siliconlandmark.com/    >

On Sun, 6 Apr 2003, Andre Guibert de Bruet wrote:

> I've just installed -current on another one of my machines and have been
> seeing "usb0: 1 scheduling overruns" messages printed to the console over
> and over under load. As the load increases, so does the frequency of the
> messages. After a bit of experimenting, I've found that large amounts of
> network traffic (I used ftp) and bzip2'ing a large dump cause the message
> to be printed roughly ten times a second.
>
> This computer had been running -stable for a few months prior and did not
> exhibit this behavior. It's a dual Athlon MP 2000+ running on an Asus
> A7M-266D with an onboard AMD-brand OHCI USB controller. The only USB
> devices that are connected are a Microsoft Internet Keyboard Pro and an
> IntelliMouse Optical (1.0A). Unplugging both devices doesn't fix the
> problem.
>
> pciconf -lv thinks the following of the controller:
> ohci0_at_pci2:0:0: class=0x0c0310 card=0x80441043 chip=0x74491022 rev=0x07 hdr=0x00
>     vendor   = 'Advanced Micro Devices (AMD)'
>     device   = 'AMD-768 USB Controller'
>     class    = serial bus
>     subclass = USB
>
> usbdevs shows:
> addr 1: OHCI root hub, AMD
>  addr 2: product 0x001c, Microsoft
>   addr 3: Microsoft IntelliMouse® Optical, Microsoft
>
> The kernel config file and dmesg can be found at:
> http://siliconlandmark.com/staff/andre/files/BLING
> http://siliconlandmark.com/staff/andre/files/BLING.dmesg
>
> uname -a:
> FreeBSD bling.properkernel.com 5.0-CURRENT FreeBSD 5.0-CURRENT #1: Sun Apr  6 16:47:32 EDT 2003     root_at_bling.properkernel.com:/usr/src/sys/i386/compile/BLING i386