perf_counter: rework context time

Since perf_counter_context is switched along with tasks, we can
maintain the context time without using the task runtime clock.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
LKML-Reference: <20090406094518.353552838@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 3 insertions, 7 deletions

diff --git a/include/linux/perf_counter.h b/include/linux/perf_counter.h
index 0f5a4005048f..7f5d353d78ac 100644
--- a/include/linux/perf_counter.h
+++ b/include/linux/perf_counter.h
@@ -477,14 +477,10 @@ struct perf_counter_context {
         struct task_struct      *task;
 
         /*
-         * time_now is the current time in nanoseconds since an arbitrary
-         * point in the past.  For per-task counters, this is based on the
-         * task clock, and for per-cpu counters it is based on the cpu clock.
-         * time_lost is an offset from the task/cpu clock, used to make it
-         * appear that time only passes while the context is scheduled in.
+         * Context clock, runs when context enabled.
          */
-        u64                     time_now;
-        u64                     time_lost;
+        u64                     time;
+        u64                     timestamp;
 #endif
 };