Revision f6771dbb27c704ce837ba3bb1dcaa53f48f76ea8 authored by Ralf Baechle on 08 November 2007, 18:02:29 UTC, committed by Ralf Baechle on 15 November 2007, 23:21:49 UTC
Shadow register support would not possibly have worked on multicore
systems.  The support code for it was also depending not on MIPS R2 but
VSMP or SMTC kernels even though it makes perfect sense with UP kernels.

SR sets are a scarce resource and the expected usage pattern is that
users actually hardcode the register set numbers in their code.  So fix
the allocator by ditching it.  Move the remaining CPU probe bits into
the generic CPU probe.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
1 parent efb9ca0
Raw File
IRQ-affinity.txt

SMP IRQ affinity, started by Ingo Molnar <mingo@redhat.com>


/proc/irq/IRQ#/smp_affinity specifies which target CPUs are permitted
for a given IRQ source. It's a bitmask of allowed CPUs. It's not allowed
to turn off all CPUs, and if an IRQ controller does not support IRQ
affinity then the value will not change from the default 0xffffffff.

Here is an example of restricting IRQ44 (eth1) to CPU0-3 then restricting
the IRQ to CPU4-7 (this is an 8-CPU SMP box):

[root@moon 44]# cat smp_affinity
ffffffff
[root@moon 44]# echo 0f > smp_affinity
[root@moon 44]# cat smp_affinity
0000000f
[root@moon 44]# ping -f h
PING hell (195.4.7.3): 56 data bytes
...
--- hell ping statistics ---
6029 packets transmitted, 6027 packets received, 0% packet loss
round-trip min/avg/max = 0.1/0.1/0.4 ms
[root@moon 44]# cat /proc/interrupts | grep 44:
 44:          0       1785       1785       1783       1783          1
1          0   IO-APIC-level  eth1
[root@moon 44]# echo f0 > smp_affinity
[root@moon 44]# ping -f h
PING hell (195.4.7.3): 56 data bytes
..
--- hell ping statistics ---
2779 packets transmitted, 2777 packets received, 0% packet loss
round-trip min/avg/max = 0.1/0.5/585.4 ms
[root@moon 44]# cat /proc/interrupts | grep 44:
 44:       1068       1785       1785       1784       1784       1069       1070       1069   IO-APIC-level  eth1
[root@moon 44]#

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