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authormerge <null@invalid>2009-01-22 13:55:32 +0000
committerAndy Green <agreen@octopus.localdomain>2009-01-22 13:55:32 +0000
commitaa6f5ffbdba45aa8e19e5048648fc6c7b25376d3 (patch)
treefbb786d0ac6f8a774fd834e9ce951197e60fbffa /Documentation/cputopology.txt
parentf2d78193eae5dccd3d588d2c8ea0866efc368332 (diff)
MERGE-via-pending-tracking-hist-MERGE-via-stable-tracking-MERGE-via-mokopatches-tracking-fix-stray-endmenu-patch-1232632040-1232632141
pending-tracking-hist top was MERGE-via-stable-tracking-MERGE-via-mokopatches-tracking-fix-stray-endmenu-patch-1232632040-1232632141 / fdf777a63bcb59e0dfd78bfe2c6242e01f6d4eb9 ... parent commitmessage: From: merge <null@invalid> MERGE-via-stable-tracking-hist-MERGE-via-mokopatches-tracking-fix-stray-endmenu-patch-1232632040 stable-tracking-hist top was MERGE-via-mokopatches-tracking-fix-stray-endmenu-patch-1232632040 / 90463bfd2d5a3c8b52f6e6d71024a00e052b0ced ... parent commitmessage: From: merge <null@invalid> MERGE-via-mokopatches-tracking-hist-fix-stray-endmenu-patch mokopatches-tracking-hist top was fix-stray-endmenu-patch / 3630e0be570de8057e7f8d2fe501ed353cdf34e6 ... parent commitmessage: From: Andy Green <andy@openmoko.com> fix-stray-endmenu.patch Signed-off-by: Andy Green <andy@openmoko.com>
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diff --git a/Documentation/cputopology.txt b/Documentation/cputopology.txt
index bd699da2466..45932ec21ce 100644
--- a/Documentation/cputopology.txt
+++ b/Documentation/cputopology.txt
@@ -31,3 +31,51 @@ not defined by include/asm-XXX/topology.h:
2) core_id: 0
3) thread_siblings: just the given CPU
4) core_siblings: just the given CPU
+
+Additionally, cpu topology information is provided under
+/sys/devices/system/cpu and includes these files. The internal
+source for the output is in brackets ("[]").
+
+ kernel_max: the maximum cpu index allowed by the kernel configuration.
+ [NR_CPUS-1]
+
+ offline: cpus that are not online because they have been
+ HOTPLUGGED off (see cpu-hotplug.txt) or exceed the limit
+ of cpus allowed by the kernel configuration (kernel_max
+ above). [~cpu_online_mask + cpus >= NR_CPUS]
+
+ online: cpus that are online and being scheduled [cpu_online_mask]
+
+ possible: cpus that have been allocated resources and can be
+ brought online if they are present. [cpu_possible_mask]
+
+ present: cpus that have been identified as being present in the
+ system. [cpu_present_mask]
+
+The format for the above output is compatible with cpulist_parse()
+[see <linux/cpumask.h>]. Some examples follow.
+
+In this example, there are 64 cpus in the system but cpus 32-63 exceed
+the kernel max which is limited to 0..31 by the NR_CPUS config option
+being 32. Note also that cpus 2 and 4-31 are not online but could be
+brought online as they are both present and possible.
+
+ kernel_max: 31
+ offline: 2,4-31,32-63
+ online: 0-1,3
+ possible: 0-31
+ present: 0-31
+
+In this example, the NR_CPUS config option is 128, but the kernel was
+started with possible_cpus=144. There are 4 cpus in the system and cpu2
+was manually taken offline (and is the only cpu that can be brought
+online.)
+
+ kernel_max: 127
+ offline: 2,4-127,128-143
+ online: 0-1,3
+ possible: 0-127
+ present: 0-3
+
+See cpu-hotplug.txt for the possible_cpus=NUM kernel start parameter
+as well as more information on the various cpumask's.