Re: [PATCH 02/13] irq: Introduce IRQD_AFFINITY_MANAGED flag

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On 06/15/2016 10:12 PM, Keith Busch wrote:
On Wed, Jun 15, 2016 at 04:06:55PM -0400, Keith Busch wrote:

0: A0 B0
1: A1 B1
2: A2 B2
3: A3 B3
4: A4 B4
5: A5 B5
6: A6 B6
7: A7 B7
8: (none)
...
31: (none)

I'll need to look at the follow on patches do to confirm, but that's
not what this should do. All CPU's should have a vector assigned because
every CPU needs to be assigned a submission context using a vector. In
your example, every vector's affinity mask should be assigned to 4 CPUs:
vector '8' starts over with A0 B0, '9' gets A1 B1, and so on.

  ^^^^^^

Sorry, I meant "CPU '8'", not "vector '8'".

Hello Keith,

Does it matter on x86 systems whether or not these interrupt vectors are also associated with a CPU with a higher CPU number? Although multiple bits can be set in /proc/irq/<n>/smp_affinity only the first bit counts on x86 platforms. In default_cpu_mask_to_apicid_and() it is easy to see that only the first bit that has been set in that mask counts on x86 systems.

Bart.
--
To unsubscribe from this list: send the line "unsubscribe linux-pci" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html



[Index of Archives]     [DMA Engine]     [Linux Coverity]     [Linux USB]     [Video for Linux]     [Linux Audio Users]     [Yosemite News]     [Linux Kernel]     [Linux SCSI]     [Greybus]

  Powered by Linux