[PATCH] Documentation: Mention chunk format for irq affinity
DORMANTno replies
From: Sebastian Poehn <hidden>
Date: 2015-07-22 08:09:39
Subsystem:
documentation, the rest · Maintainers:
Jonathan Corbet, Linus Torvalds
It may not be obvious for everyone that bitmasks in proc require
32bit chunking
Signed-off-by: Sebastian Poehn <redacted>
---
Documentation/IRQ-affinity.txt | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/Documentation/IRQ-affinity.txt b/Documentation/IRQ-affinity.txt
index 01a6751..d873dab 100644
--- a/Documentation/IRQ-affinity.txt
+++ b/Documentation/IRQ-affinity.txt@@ -55,6 +55,11 @@ round-trip min/avg/max = 0.1/0.5/585.4 ms This time around IRQ44 was delivered only to the last four processors. i.e counters for the CPU0-3 did not change. +Note that you have to split the bitmask to chunks when using more that 32 cpus: +[root@moon 44]# echo 80,00000000 > smp_affinity +[root@moon 44]# cat smp_affinity +80,00000000 + Here is an example of limiting that same irq (44) to cpus 1024 to 1031: [root@moon 44]# echo 1024-1031 > smp_affinity_list
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2.4.3