2009-09-01 15:06:34

by Christoph Lameter

Subject: Re: RFC: THE OFFLINE SCHEDULER

On Mon, 31 Aug 2009, Roland Dreier wrote:

>
> > Some devices now have per cpu threads. See f.e. Mellanox IB drivers. Maybe
> > there is a way to restrict that.
>
> AFAIK the Mellanox drivers just create a single-threaded workqueue.

Ok then these per cpu irqs are there to support something different? There
are per cpu irqs here. Seems to be hardware supported?

62: 13824 0 0 0 0 0
0 0 0 0 0 0 0
0 0 0 IR-PCI-MSI-edge mlx4-comp-0
63: 0 0 0 0 0 0
0 0 0 0 0 0 0
0 0 0 IR-PCI-MSI-edge mlx4-comp-1
64: 0 0 0 0 0 0
0 0 0 0 0 0 0
0 0 0 IR-PCI-MSI-edge mlx4-comp-2
65: 0 0 0 0 0 0
0 0 0 0 0 0 0
0 0 0 IR-PCI-MSI-edge mlx4-comp-3
66: 0 0 0 0 0 0
0 0 0 0 0 0 0
0 0 0 IR-PCI-MSI-edge mlx4-comp-4
67: 0 0 0 0 0 0
0 0 0 0 0 0 0
0 0 0 IR-PCI-MSI-edge mlx4-comp-5
68: 0 0 0 0 0 0
0 0 0 0 0 0 0
0 0 0 IR-PCI-MSI-edge mlx4-comp-6
69: 0 0 0 0 0 0
0 0 0 0 0 0 0
0 0 0 IR-PCI-MSI-edge mlx4-comp-7
70: 0 0 0 0 0 0
0 0 0 0 0 0 0
0 0 0 IR-PCI-MSI-edge mlx4-comp-8
71: 0 0 0 0 0 0
0 0 0 0 0 0 0
0 0 0 IR-PCI-MSI-edge mlx4-comp-9
72: 0 0 0 0 0 0
0 0 0 0 0 0 0
0 0 0 IR-PCI-MSI-edge mlx4-comp-10
73: 0 0 0 0 0 0
0 0 0 0 0 0 0
0 0 0 IR-PCI-MSI-edge mlx4-comp-11
74: 0 0 0 0 0 0
0 0 0 0 0 0 0
0 0 0 IR-PCI-MSI-edge mlx4-comp-12
75: 0 0 0 0 0 0
0 0 0 0 0 0 0
0 0 0 IR-PCI-MSI-edge mlx4-comp-13
76: 0 0 0 0 0 0
0 0 0 0 0 0 0
0 0 0 IR-PCI-MSI-edge mlx4-comp-14
77: 0 0 0 0 0 0
0 0 0 0 0 0 0
0 0 0 IR-PCI-MSI-edge mlx4-comp-15
78: 3225 0 0 0 0 0
0 0 0 0 0 0 0
0 0 0 IR-PCI-MSI-edge mlx4-async
79: 1832 0 0 0 0 0
0 0 0 0 0 0 0
0 0 0 IR-PCI-MSI-edge eth0-0
80: 5546 0 0 0 0 0
0 0 0 0 0 0 0
0 0 0 IR-PCI-MSI-edge eth0-1
81: 2604 0 0 0 0 0
0 0 0 0 0 0 0
0 0 0 IR-PCI-MSI-edge eth0-2
82: 124 0 0 0 0 0
0 0 0 0 0 0 0
0 0 0 IR-PCI-MSI-edge eth0-3
83: 743126 0 0 0 0 0
0 0 0 0 0 0 0
0 0 0 IR-PCI-MSI-edge eth0-4
84: 857 0 0 0 0 0
0 0 0 0 0 0 0
0 0 0 IR-PCI-MSI-edge eth0-5
85: 321 0 0 0 0 0
0 0 0 0 0 0 0
0 0 0 IR-PCI-MSI-edge eth0-6
86: 2296 0 0 0 0 0
0 0 0 0 0 0 0
0 0 0 IR-PCI-MSI-edge eth0-7

2009-09-01 16:15:46

by Roland Dreier

Subject: Re: RFC: THE OFFLINE SCHEDULER

> Ok then these per cpu irqs are there to support something different? There
> are per cpu irqs here. Seems to be hardware supported?

Yes, the driver now creates per-cpu IRQs for completions. However if
you don't trigger any completion events then you won't get any
interrupts. That's different from the workqueues, which are used to
poll the hardware for port changes and internal errors (and which are
single-threaded and can be put on whatever "system services" CPU you want)

- R.