Add scaled time to taskstats based process accounting

This adds items to the taststats struct to account for user and system
time based on scaling the CPU frequency and instruction issue rates.

Adds account_(user|system)_time_scaled callbacks which architectures
can use to account for time using this mechanism.

Signed-off-by: Michael Neuling <mikey@neuling.org>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Jay Lan <jlan@engr.sgi.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

3 files changed, 12 insertions, 3 deletions

diff --git a/include/linux/kernel_stat.h b/include/linux/kernel_stat.h
index 12bf44f083f5..e8ffce898bf9 100644
--- a/include/linux/kernel_stat.h
+++ b/include/linux/kernel_stat.h
@@ -53,7 +53,9 @@ static inline int kstat_irqs(int irq)
 }
 
 extern void account_user_time(struct task_struct *, cputime_t);
+extern void account_user_time_scaled(struct task_struct *, cputime_t);
 extern void account_system_time(struct task_struct *, int, cputime_t);
+extern void account_system_time_scaled(struct task_struct *, cputime_t);
 extern void account_steal_time(struct task_struct *, cputime_t);
 
 #endif /* _LINUX_KERNEL_STAT_H */
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 269b234609b8..7accc04e23ab 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -991,7 +991,7 @@ struct task_struct {
         int __user *clear_child_tid;            /* CLONE_CHILD_CLEARTID */
 
         unsigned int rt_priority;
-        cputime_t utime, stime;
+        cputime_t utime, stime, utimescaled, stimescaled;
         cputime_t gtime;
         unsigned long nvcsw, nivcsw; /* context switch counts */
         struct timespec start_time;             /* monotonic time */
diff --git a/include/linux/taskstats.h b/include/linux/taskstats.h
index dce1ed204972..92bfd1c153fb 100644
--- a/include/linux/taskstats.h
+++ b/include/linux/taskstats.h
@@ -31,7 +31,7 @@
  */
 
 
-#define TASKSTATS_VERSION       5
+#define TASKSTATS_VERSION       6
 #define TS_COMM_LEN             32      /* should be >= TASK_COMM_LEN
                                          * in linux/sched.h */
 
@@ -85,9 +85,12 @@ struct taskstats {
          * On some architectures, value will adjust for cpu time stolen
          * from the kernel in involuntary waits due to virtualization.
          * Value is cumulative, in nanoseconds, without a corresponding count
-         * and wraps around to zero silently on overflow
+         * and wraps around to zero silently on overflow.  The
+         * _scaled_ version accounts for cpus which can scale the
+         * number of instructions executed each cycle.
          */
         __u64   cpu_run_real_total;
+        __u64   cpu_scaled_run_real_total;
 
         /* cpu "virtual" running time
          * Uses time intervals seen by the kernel i.e. no adjustment
@@ -142,6 +145,10 @@ struct taskstats {
         __u64   write_char;             /* bytes written */
         __u64   read_syscalls;          /* read syscalls */
         __u64   write_syscalls;         /* write syscalls */
+
+        /* time accounting for SMT machines */
+        __u64   ac_utimescaled;         /* utime scaled on frequency etc */
+        __u64   ac_stimescaled;         /* stime scaled on frequency etc */
         /* Extended accounting fields end */
 
 #define TASKSTATS_HAS_IO_ACCOUNTING