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| author | David S. Miller <davem@davemloft.net> | 2017-07-21 03:38:43 +0100 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2017-07-21 03:38:43 +0100 |
| commit | 7a68ada6ec7d88c68057d3a4c2a517eb94289976 (patch) | |
| tree | 51cd586e74fc92bfbdf382fa1544a235d908b25c /Documentation/IRQ-affinity.txt | |
| parent | 760446f967678e14ee1b6464ee1bb8562f299fa6 (diff) | |
| parent | 96080f697786e0a30006fcbcc5b53f350fcb3e9f (diff) | |
| download | blackbird-obmc-linux-7a68ada6ec7d88c68057d3a4c2a517eb94289976.tar.gz blackbird-obmc-linux-7a68ada6ec7d88c68057d3a4c2a517eb94289976.zip | |
Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
Diffstat (limited to 'Documentation/IRQ-affinity.txt')
| -rw-r--r-- | Documentation/IRQ-affinity.txt | 75 |
1 files changed, 40 insertions, 35 deletions
diff --git a/Documentation/IRQ-affinity.txt b/Documentation/IRQ-affinity.txt index 01a675175a36..29da5000836a 100644 --- a/Documentation/IRQ-affinity.txt +++ b/Documentation/IRQ-affinity.txt @@ -1,8 +1,11 @@ +================ +SMP IRQ affinity +================ + ChangeLog: - Started by Ingo Molnar <mingo@redhat.com> - Update by Max Krasnyansky <maxk@qualcomm.com> + - 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 @@ -16,50 +19,52 @@ 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): +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]# 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 + [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 +:: + + [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: +Here is an example of limiting that same irq (44) to cpus 1024 to 1031:: -[root@moon 44]# echo 1024-1031 > smp_affinity_list -[root@moon 44]# cat smp_affinity_list -1024-1031 + [root@moon 44]# echo 1024-1031 > smp_affinity_list + [root@moon 44]# cat smp_affinity_list + 1024-1031 Note that to do this with a bitmask would require 32 bitmasks of zero to follow the pertinent one. |
