perf_counter: Allow sharing of output channels

Provide the ability to configure a counter to send its output
to another (already existing) counter's output stream.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: stephane eranian <eranian@googlemail.com>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <20090819092023.980284148@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 5 insertions, 0 deletions

diff --git a/include/linux/perf_counter.h b/include/linux/perf_counter.h
index b53f7006cc4e..e022b847c90d 100644
--- a/include/linux/perf_counter.h
+++ b/include/linux/perf_counter.h
@@ -216,6 +216,7 @@ struct perf_counter_attr {
 #define PERF_COUNTER_IOC_REFRESH        _IO ('$', 2)
 #define PERF_COUNTER_IOC_RESET          _IO ('$', 3)
 #define PERF_COUNTER_IOC_PERIOD         _IOW('$', 4, u64)
+#define PERF_COUNTER_IOC_SET_OUTPUT     _IO ('$', 5)
 
 enum perf_counter_ioc_flags {
         PERF_IOC_FLAG_GROUP             = 1U << 0,
@@ -415,6 +416,9 @@ enum perf_callchain_context {
         PERF_CONTEXT_MAX                = (__u64)-4095,
 };
 
+#define PERF_FLAG_FD_NO_GROUP   (1U << 0)
+#define PERF_FLAG_FD_OUTPUT     (1U << 1)
+
 #ifdef __KERNEL__
 /*
  * Kernel-internal data types and definitions:
@@ -536,6 +540,7 @@ struct perf_counter {
         struct list_head                sibling_list;
         int                             nr_siblings;
         struct perf_counter             *group_leader;
+        struct perf_counter             *output;
         const struct pmu                *pmu;
 
         enum perf_counter_active_state  state;