3 files changed, 34 insertions, 2 deletions

diff --git a/arch/powerpc/kernel/asm-offsets.c b/arch/powerpc/kernel/asm-offsets.c
index 0ae5d57b9368..2c8e756d19a3 100644
--- a/arch/powerpc/kernel/asm-offsets.c
+++ b/arch/powerpc/kernel/asm-offsets.c
@@ -141,6 +141,7 @@ int main(void)
         DEFINE(PACALPPACAPTR, offsetof(struct paca_struct, lppaca_ptr));
         DEFINE(PACAHWCPUID, offsetof(struct paca_struct, hw_cpu_id));
         DEFINE(PACA_STARTPURR, offsetof(struct paca_struct, startpurr));
+        DEFINE(PACA_STARTSPURR, offsetof(struct paca_struct, startspurr));
         DEFINE(PACA_USER_TIME, offsetof(struct paca_struct, user_time));
         DEFINE(PACA_SYSTEM_TIME, offsetof(struct paca_struct, system_time));
         DEFINE(PACA_SLBSHADOWPTR, offsetof(struct paca_struct, slb_shadow_ptr));
diff --git a/arch/powerpc/kernel/time.c b/arch/powerpc/kernel/time.c
index 863a5d6d9b18..9eb3284deac4 100644
--- a/arch/powerpc/kernel/time.c
+++ b/arch/powerpc/kernel/time.c
@@ -212,23 +212,44 @@ static u64 read_purr(void)
 }
 
 /*
+ * Read the SPURR on systems that have it, otherwise the purr
+ */
+static u64 read_spurr(u64 purr)
+{
+        if (cpu_has_feature(CPU_FTR_SPURR))
+                return mfspr(SPRN_SPURR);
+        return purr;
+}
+
+/*
  * Account time for a transition between system, hard irq
  * or soft irq state.
  */
 void account_system_vtime(struct task_struct *tsk)
 {
-        u64 now, delta;
+        u64 now, nowscaled, delta, deltascaled;
         unsigned long flags;
 
         local_irq_save(flags);
         now = read_purr();
         delta = now - get_paca()->startpurr;
         get_paca()->startpurr = now;
+        nowscaled = read_spurr(now);
+        deltascaled = nowscaled - get_paca()->startspurr;
+        get_paca()->startspurr = nowscaled;
         if (!in_interrupt()) {
+                /* deltascaled includes both user and system time.
+                 * Hence scale it based on the purr ratio to estimate
+                 * the system time */
+                deltascaled = deltascaled * get_paca()->system_time /
+                        (get_paca()->system_time + get_paca()->user_time);
                 delta += get_paca()->system_time;
                 get_paca()->system_time = 0;
         }
         account_system_time(tsk, 0, delta);
+        get_paca()->purrdelta = delta;
+        account_system_time_scaled(tsk, deltascaled);
+        get_paca()->spurrdelta = deltascaled;
         local_irq_restore(flags);
 }
 
@@ -240,11 +261,17 @@ void account_system_vtime(struct task_struct *tsk)
  */
 void account_process_vtime(struct task_struct *tsk)
 {
-        cputime_t utime;
+        cputime_t utime, utimescaled;
 
         utime = get_paca()->user_time;
         get_paca()->user_time = 0;
         account_user_time(tsk, utime);
+
+        /* Estimate the scaled utime by scaling the real utime based
+         * on the last spurr to purr ratio */
+        utimescaled = utime * get_paca()->spurrdelta / get_paca()->purrdelta;
+        get_paca()->spurrdelta = get_paca()->purrdelta = 0;
+        account_user_time_scaled(tsk, utimescaled);
 }
 
 static void account_process_time(struct pt_regs *regs)
@@ -266,6 +293,7 @@ struct cpu_purr_data {
         int     initialized;                    /* thread is running */
         u64     tb;                     /* last TB value read */
         u64     purr;                   /* last PURR value read */
+        u64     spurr;                  /* last SPURR value read */
 };
 
 /*
diff --git a/include/asm-powerpc/paca.h b/include/asm-powerpc/paca.h
index fcd7b428ed0b..98c6bd5756b7 100644
--- a/include/asm-powerpc/paca.h
+++ b/include/asm-powerpc/paca.h
@@ -114,6 +114,9 @@ struct paca_struct {
         u64 user_time;                  /* accumulated usermode TB ticks */
         u64 system_time;                /* accumulated system TB ticks */
         u64 startpurr;                  /* PURR/TB value snapshot */
+        u64 startspurr;                 /* SPURR value snapshot */
+        u64 purrdelta;                  /* FIXME: document */
+        u64 spurrdelta;                 /* FIXME: document */
 };
 
 extern struct paca_struct paca[];