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authorStephane Eranian <eranian@google.com>2010-02-01 14:50:01 +0200
committerIngo Molnar <mingo@elte.hu>2010-02-04 09:59:50 +0100
commit447a194b393f32699607fd99617a40abd6a95114 (patch)
tree7d202a6ad8f80c913a4e3d439eedf5ba0abbbf39 /include
parentfce877e3a429940a986e085a41e8b57f2d922e36 (diff)
downloadop-kernel-dev-447a194b393f32699607fd99617a40abd6a95114.zip
op-kernel-dev-447a194b393f32699607fd99617a40abd6a95114.tar.gz
perf_events, x86: Fix bug in hw_perf_enable()
We cannot assume that because hwc->idx == assign[i], we can avoid reprogramming the counter in hw_perf_enable(). The event may have been scheduled out and another event may have been programmed into this counter. Thus, we need a more robust way of verifying if the counter still contains config/data related to an event. This patch adds a generation number to each counter on each cpu. Using this mechanism we can verify reliabilty whether the content of a counter corresponds to an event. Signed-off-by: Stephane Eranian <eranian@google.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Mike Galbraith <efault@gmx.de> Cc: Paul Mackerras <paulus@samba.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> LKML-Reference: <4b66dc67.0b38560a.1635.ffffae18@mx.google.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'include')
-rw-r--r--include/linux/perf_event.h2
1 files changed, 2 insertions, 0 deletions
diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index 556b0f4..071a7db 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -478,9 +478,11 @@ struct hw_perf_event {
union {
struct { /* hardware */
u64 config;
+ u64 last_tag;
unsigned long config_base;
unsigned long event_base;
int idx;
+ int last_cpu;
};
struct { /* software */
s64 remaining;
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