perf_counter: hrtimer based sampling for software time events

Use hrtimers to profile timer based sampling for the software time
counters.

This allows platforms without hardware counter support to still
perform sample based profiling.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 14 insertions, 6 deletions

diff --git a/include/linux/perf_counter.h b/include/linux/perf_counter.h
index 4b14a8e9dbf5..dfb4c7ce18b3 100644
--- a/include/linux/perf_counter.h
+++ b/include/linux/perf_counter.h
@@ -114,6 +114,7 @@ struct perf_counter_hw_event {
 #include <linux/rculist.h>
 #include <linux/rcupdate.h>
 #include <linux/spinlock.h>
+#include <linux/hrtimer.h>
 #include <asm/atomic.h>
 
 struct task_struct;
@@ -123,12 +124,19 @@ struct task_struct;
  */
 struct hw_perf_counter {
 #ifdef CONFIG_PERF_COUNTERS
-        u64                             config;
-        unsigned long                   config_base;
-        unsigned long                   counter_base;
-        int                             nmi;
-        unsigned int                    idx;
-        atomic64_t                      count; /* software */
+        union {
+                struct { /* hardware */
+                        u64                             config;
+                        unsigned long                   config_base;
+                        unsigned long                   counter_base;
+                        int                             nmi;
+                        unsigned int                    idx;
+                };
+                union { /* software */
+                        atomic64_t                      count;
+                        struct hrtimer                  hrtimer;
+                };
+        };
         atomic64_t                      prev_count;
         u64                             irq_period;
         atomic64_t                      period_left;