Re: [PATCH] fix stolen time for SMT without LPAR

[Michael Neuling <mikey@neuling.org>]

For POWERPC, stolen time accounts for cycles lost to the hypervisor or
PURR cycles attributed to the other SMT thread.  Hence, when a PURR is
available, we should still calculate stolen time, irrespective of being
virtualised.

Signed-off-by: Michael Neuling <mikey@neuling.org>
---
Updated to fix link error when CONFIG_PPC_SPLPAR is off.  

 arch/powerpc/kernel/time.c |    8 +++++---
 include/asm-powerpc/time.h |    2 +-
 2 files changed, 6 insertions(+), 4 deletions(-)

Index: linux-2.6-ozlabs/arch/powerpc/kernel/time.c
===================================================================
--- linux-2.6-ozlabs.orig/arch/powerpc/kernel/time.c
+++ linux-2.6-ozlabs/arch/powerpc/kernel/time.c
@@ -214,7 +214,6 @@ static void account_process_time(struct 
  	run_posix_cpu_timers(current);
 }
 
-#ifdef CONFIG_PPC_SPLPAR
 /*
  * Stuff for accounting stolen time.
  */
@@ -244,7 +243,8 @@ void snapshot_timebases(void)
 {
 	int cpu;
 
-	if (!cpu_has_feature(CPU_FTR_PURR))
+	if (!cpu_has_feature(CPU_FTR_PURR) &&
+	    !firmware_has_feature(FW_FEATURE_SPLPAR))
 		return;
 	for_each_possible_cpu(cpu)
 		spin_lock_init(&per_cpu(cpu_purr_data, cpu).lock);
@@ -257,7 +257,8 @@ void calculate_steal_time(void)
 	s64 stolen;
 	struct cpu_purr_data *pme;
 
-	if (!cpu_has_feature(CPU_FTR_PURR))
+	if (!cpu_has_feature(CPU_FTR_PURR) &&
+	    !firmware_has_feature(FW_FEATURE_SPLPAR))
 		return;
 	pme = &per_cpu(cpu_purr_data, smp_processor_id());
 	if (!pme->initialized)
@@ -273,6 +274,7 @@ void calculate_steal_time(void)
 	spin_unlock(&pme->lock);
 }
 
+#ifdef CONFIG_PPC_SPLPAR
 /*
  * Must be called before the cpu is added to the online map when
  * a cpu is being brought up at runtime.
Index: linux-2.6-ozlabs/include/asm-powerpc/time.h
===================================================================
--- linux-2.6-ozlabs.orig/include/asm-powerpc/time.h
+++ linux-2.6-ozlabs/include/asm-powerpc/time.h
@@ -232,7 +232,7 @@ extern void account_process_vtime(struct
 #define account_process_vtime(tsk)		do { } while (0)
 #endif
 
-#if defined(CONFIG_VIRT_CPU_ACCOUNTING) && defined(CONFIG_PPC_SPLPAR)
+#if defined(CONFIG_VIRT_CPU_ACCOUNTING)
 extern void calculate_steal_time(void);
 extern void snapshot_timebases(void);
 #else