View Full Version : [ubuntu] SATA and Network problems

January 5th, 2010, 03:38 PM
This almost started out as yet another samba is slow problem. But I've narrowed things down a bit.

I have a Promise PDC20376 on board SATA controller. I just installed a new SATA drive in it. Also I have an onboard Broadcom BCM4401 ethernet port.

When I do file transfers which do not involve the SATA drive, so the file transfer is going to the IDE drive, I get transfer rates of about 10 MByte/sec (100 mbit network). When I transfer to/from the SATA drive it starts out at about 10 MByte/sec but quickly drops down to under 1MByte/sec and pretty much stays there throughout the remainder of the transfer. Iperf shows similar transfer as the non-SATA transfer.

I thought it might be a problem with the drive. hdparm -Tt /dev/sdb shows decent throughput on the drive at around 60 MByte/sec. No smart problems. I can transfer files from the IDE to the SATA at comparable rates.

If I do a transfer over the network using the IDE drive I get good throughput. If I then do non network access to the SATA drive (copying a local file) the network traffic bottoms out.

So I appear to be facing a hardware conflict.

$ cat /proc/interrupts
0: 48 IO-APIC-edge timer
1: 4 IO-APIC-edge i8042
3: 4 IO-APIC-edge
4: 4 IO-APIC-edge
6: 5 IO-APIC-edge floppy
7: 0 IO-APIC-edge parport0
8: 0 IO-APIC-edge rtc0
14: 55196 IO-APIC-edge ata_piix
15: 0 IO-APIC-edge ata_piix
16: 0 IO-APIC-fasteoi uhci_hcd:usb2, mga@pci:0000:01:00.0
17: 101 IO-APIC-fasteoi Intel 82801DB-ICH4
18: 0 IO-APIC-fasteoi uhci_hcd:usb4
19: 0 IO-APIC-fasteoi uhci_hcd:usb3
20: 1686435 IO-APIC-fasteoi eth4
22: 2 IO-APIC-fasteoi acpi, ohci1394
23: 3694 IO-APIC-fasteoi sata_promise, ehci_hcd:usb1
NMI: 0 Non-maskable interrupts
LOC: 9708460 Local timer interrupts
SPU: 0 Spurious interrupts
CNT: 0 Performance counter interrupts
PND: 0 Performance pending work
RES: 0 Rescheduling interrupts
CAL: 0 Function call interrupts
TLB: 0 TLB shootdowns
TRM: 0 Thermal event interrupts
THR: 0 Threshold APIC interrupts
MCE: 0 Machine check exceptions
MCP: 117 Machine check polls
ERR: 0
MIS: 0
$It doesn't appear to be an interrupt conflict. The SATA is on IRQ 23 and the network on IRQ 20.

I'm out of ideas. I'm going to try and locate a PCI SATA and/or PCI network card to see if I can resolve it that way but other than that, any suggestions?