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author | Ingo Molnar <mingo@elte.hu> | 2008-07-15 23:12:58 +0200 |
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committer | Ingo Molnar <mingo@elte.hu> | 2008-07-15 23:12:58 +0200 |
commit | 1e09481365ce248dbb4eb06dad70129bb5807037 (patch) | |
tree | c0cff5bef95c8b5e7486f144718ade9a06c284dc /Documentation/filesystems/proc.txt | |
parent | 3e2f69fdd1b00166e7d589bce56b2d36a9e74374 (diff) | |
parent | b9d2252c1e44fa83a4e65fdc9eb93db6297c55af (diff) | |
download | blackbird-op-linux-1e09481365ce248dbb4eb06dad70129bb5807037.tar.gz blackbird-op-linux-1e09481365ce248dbb4eb06dad70129bb5807037.zip |
Merge branch 'linus' into core/softlockup
Conflicts:
kernel/softlockup.c
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'Documentation/filesystems/proc.txt')
-rw-r--r-- | Documentation/filesystems/proc.txt | 29 |
1 files changed, 18 insertions, 11 deletions
diff --git a/Documentation/filesystems/proc.txt b/Documentation/filesystems/proc.txt index dbc3c6a3650f..7f268f327d75 100644 --- a/Documentation/filesystems/proc.txt +++ b/Documentation/filesystems/proc.txt @@ -380,28 +380,35 @@ i386 and x86_64 platforms support the new IRQ vector displays. Of some interest is the introduction of the /proc/irq directory to 2.4. It could be used to set IRQ to CPU affinity, this means that you can "hook" an IRQ to only one CPU, or to exclude a CPU of handling IRQs. The contents of the -irq subdir is one subdir for each IRQ, and one file; prof_cpu_mask +irq subdir is one subdir for each IRQ, and two files; default_smp_affinity and +prof_cpu_mask. For example > ls /proc/irq/ 0 10 12 14 16 18 2 4 6 8 prof_cpu_mask - 1 11 13 15 17 19 3 5 7 9 + 1 11 13 15 17 19 3 5 7 9 default_smp_affinity > ls /proc/irq/0/ smp_affinity -The contents of the prof_cpu_mask file and each smp_affinity file for each IRQ -is the same by default: +smp_affinity is a bitmask, in which you can specify which CPUs can handle the +IRQ, you can set it by doing: - > cat /proc/irq/0/smp_affinity - ffffffff + > echo 1 > /proc/irq/10/smp_affinity + +This means that only the first CPU will handle the IRQ, but you can also echo +5 which means that only the first and fourth CPU can handle the IRQ. -It's a bitmask, in which you can specify which CPUs can handle the IRQ, you can -set it by doing: +The contents of each smp_affinity file is the same by default: + + > cat /proc/irq/0/smp_affinity + ffffffff - > echo 1 > /proc/irq/prof_cpu_mask +The default_smp_affinity mask applies to all non-active IRQs, which are the +IRQs which have not yet been allocated/activated, and hence which lack a +/proc/irq/[0-9]* directory. -This means that only the first CPU will handle the IRQ, but you can also echo 5 -which means that only the first and fourth CPU can handle the IRQ. +prof_cpu_mask specifies which CPUs are to be profiled by the system wide +profiler. Default value is ffffffff (all cpus). The way IRQs are routed is handled by the IO-APIC, and it's Round Robin between all the CPUs which are allowed to handle it. As usual the kernel has |