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Old 10-08-08, 12:45 AM   #4
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Join Date: Apr 2005
Posts: 75
Default Re: What better, PCI-X MSI or Wired IRQ? [177.80]

Originally Posted by SilentLexx View Post
I'm testing now MSI. Very interesting... Performance is good, for stability will see I have now 2 devices on msi interrupts bus:

cat /proc/interrupts | grep -i msi
221: 37100 202 PCI-MSI-edge eth1
222: 51351 77 PCI-MSI-edge nvidia

Message Signaled Interrupts (MSI and MSI-X) (PCI_MSI)

This allows device drivers to enable MSI (Message Signaled
Interrupts). Message Signaled Interrupts enable a device to
generate an interrupt using an inbound Memory Write on its
PCI bus instead of asserting a device IRQ pin.

Use of PCI MSI interrupts can be disabled at kernel boot time
by using the 'pci=nomsi' option. This disables MSI for the
entire system.
looks interesting, does it need some extra configurations on my debian sid?

i'm using a customized kernel 2.6.26.

zcat /proc/config.gz | grep MSI


lspci -v, nvidia related output, so i can tell it's MSI disabled at this moment, am i right?

02:00.0 VGA compatible controller: nVidia Corporation GeForce 8500 GT (rev a1)
Subsystem: ASUSTeK Computer Inc. Device 8245
Flags: bus master, fast devsel, latency 0, IRQ 16
Memory at fa000000 (32-bit, non-prefetchable) [size=16M]
Memory at e0000000 (64-bit, prefetchable) [size=256M]
Memory at f8000000 (64-bit, non-prefetchable) [size=32M]
I/O ports at bc00 [size=128]
[virtual] Expansion ROM at fb000000 [disabled] [size=128K]
Capabilities: [60] Power Management version 2
Capabilities: [68] Message Signalled Interrupts: Mask- 64bit+ Queue=0/0 Enable-
Capabilities: [78] Express Endpoint, MSI 00
Capabilities: [100] Virtual Channel <?>
Capabilities: [128] Power Budgeting <?>
Capabilities: [600] Vendor Specific Information <?>
Kernel driver in use: nvidia
Kernel modules: nvidia
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