mirror of
https://github.com/edk2-porting/linux-next.git
synced 2024-12-16 17:23:55 +08:00
4b060420a5
Manually adjusting the smp_affinity for IRQ's becomes unwieldy when the cpu count is large. Setting smp affinity to cpus 256 to 263 would be: echo 000000ff,00000000,00000000,00000000,00000000,00000000,00000000,00000000 > smp_affinity instead of: echo 256-263 > smp_affinity_list Think about what it looks like for cpus around say, 4088 to 4095. We already have many alternate "list" interfaces: /sys/devices/system/cpu/cpuX/indexY/shared_cpu_list /sys/devices/system/cpu/cpuX/topology/thread_siblings_list /sys/devices/system/cpu/cpuX/topology/core_siblings_list /sys/devices/system/node/nodeX/cpulist /sys/devices/pci***/***/local_cpulist Add a companion interface, smp_affinity_list to use cpu lists instead of cpu maps. This conforms to other companion interfaces where both a map and a list interface exists. This required adding a bitmap_parselist_user() function in a manner similar to the bitmap_parse_user() function. [akpm@linux-foundation.org: make __bitmap_parselist() static] Signed-off-by: Mike Travis <travis@sgi.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Jack Steiner <steiner@sgi.com> Cc: Lee Schermerhorn <lee.schermerhorn@hp.com> Cc: Andy Shevchenko <andy.shevchenko@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
66 lines
2.5 KiB
Plaintext
66 lines
2.5 KiB
Plaintext
ChangeLog:
|
|
Started by Ingo Molnar <mingo@redhat.com>
|
|
Update by Max Krasnyansky <maxk@qualcomm.com>
|
|
|
|
SMP IRQ affinity
|
|
|
|
/proc/irq/IRQ#/smp_affinity and /proc/irq/IRQ#/smp_affinity_list specify
|
|
which target CPUs are permitted for a given IRQ source. It's a bitmask
|
|
(smp_affinity) or cpu list (smp_affinity_list) 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 of all cpus.
|
|
|
|
/proc/irq/default_smp_affinity specifies default affinity mask that applies
|
|
to all non-active IRQs. Once IRQ is allocated/activated its affinity bitmask
|
|
will be set to the default mask. It can then be changed as described above.
|
|
Default mask is 0xffffffff.
|
|
|
|
Here is an example of restricting IRQ44 (eth1) to CPU0-3 then restricting
|
|
it to CPU4-7 (this is an 8-CPU SMP box):
|
|
|
|
[root@moon 44]# cd /proc/irq/44
|
|
[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 'CPU\|44:'
|
|
CPU0 CPU1 CPU2 CPU3 CPU4 CPU5 CPU6 CPU7
|
|
44: 1068 1785 1785 1783 0 0 0 0 IO-APIC-level eth1
|
|
|
|
As can be seen from the line above IRQ44 was delivered only to the first four
|
|
processors (0-3).
|
|
Now lets restrict that IRQ to CPU(4-7).
|
|
|
|
[root@moon 44]# echo f0 > smp_affinity
|
|
[root@moon 44]# cat smp_affinity
|
|
000000f0
|
|
[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 | 'CPU\|44:'
|
|
CPU0 CPU1 CPU2 CPU3 CPU4 CPU5 CPU6 CPU7
|
|
44: 1068 1785 1785 1783 1784 1069 1070 1069 IO-APIC-level eth1
|
|
|
|
This time around IRQ44 was delivered only to the last four processors.
|
|
i.e counters for the CPU0-3 did not change.
|
|
|
|
Here is an example of limiting that same irq (44) to cpus 1024 to 1031:
|
|
|
|
[root@moon 44]# echo 1024-1031 > smp_affinity
|
|
[root@moon 44]# cat smp_affinity
|
|
1024-1031
|
|
|
|
Note that to do this with a bitmask would require 32 bitmasks of zero
|
|
to follow the pertinent one.
|