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authorPaul Mackerras <paulus@samba.org>2010-03-10 20:36:09 +1100
committerIngo Molnar <mingo@elte.hu>2010-03-11 13:36:53 +0100
commita12b51c478899fe0b7e874a559b05ba35f1128ee (patch)
tree25b9911c1932c13fd8b468aa18eb17982ba31b59 /tools/perf/Makefile
parent220b140b52ab6cc133f674a7ffec8fa792054f25 (diff)
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op-kernel-dev-a12b51c478899fe0b7e874a559b05ba35f1128ee.tar.gz
perf tools: Fix sparse CPU numbering related bugs
At present, the perf subcommands that do system-wide monitoring (perf stat, perf record and perf top) don't work properly unless the online cpus are numbered 0, 1, ..., N-1. These tools ask for the number of online cpus with sysconf(_SC_NPROCESSORS_ONLN) and then try to create events for cpus 0, 1, ..., N-1. This creates problems for systems where the online cpus are numbered sparsely. For example, a POWER6 system in single-threaded mode (i.e. only running 1 hardware thread per core) will have only even-numbered cpus online. This fixes the problem by reading the /sys/devices/system/cpu/online file to find out which cpus are online. The code that does that is in tools/perf/util/cpumap.[ch], and consists of a read_cpu_map() function that sets up a cpumap[] array and returns the number of online cpus. If /sys/devices/system/cpu/online can't be read or can't be parsed successfully, it falls back to using sysconf to ask how many cpus are online and sets up an identity map in cpumap[]. The perf record, perf stat and perf top code then calls read_cpu_map() in the system-wide monitoring case (instead of sysconf) and uses cpumap[] to get the cpu numbers to pass to perf_event_open. Signed-off-by: Paul Mackerras <paulus@samba.org> Cc: Anton Blanchard <anton@samba.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@infradead.org> LKML-Reference: <20100310093609.GA3959@brick.ozlabs.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'tools/perf/Makefile')
-rw-r--r--tools/perf/Makefile2
1 files changed, 2 insertions, 0 deletions
diff --git a/tools/perf/Makefile b/tools/perf/Makefile
index 2d53738..5840499 100644
--- a/tools/perf/Makefile
+++ b/tools/perf/Makefile
@@ -387,6 +387,7 @@ LIB_H += util/thread.h
LIB_H += util/trace-event.h
LIB_H += util/probe-finder.h
LIB_H += util/probe-event.h
+LIB_H += util/cpumap.h
LIB_OBJS += util/abspath.o
LIB_OBJS += util/alias.o
@@ -433,6 +434,7 @@ LIB_OBJS += util/sort.o
LIB_OBJS += util/hist.o
LIB_OBJS += util/probe-event.o
LIB_OBJS += util/util.o
+LIB_OBJS += util/cpumap.o
BUILTIN_OBJS += builtin-annotate.o
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