[PATCH v5 3/5] powerpc/pseries: Account for SPURR ticks on idle CPUs

[Gautham R. Shenoy]

From: "Gautham R. Shenoy" <e...@linux.vnet.ibm.com>

On Pseries LPARs, to calculate utilization, we need to know the
[S]PURR ticks when the CPUs were busy or idle.

Via pseries_idle_prolog(), pseries_idle_epilog(), we track the idle
PURR ticks in the VPA variable "wait_state_cycles". This patch extends
the support to account for the idle SPURR ticks.

Signed-off-by: Gautham R. Shenoy <e...@linux.vnet.ibm.com>
---
 arch/powerpc/include/asm/idle.h        | 17 +++++++++++++++++
 arch/powerpc/platforms/pseries/setup.c |  2 ++
 2 files changed, 19 insertions(+)

diff --git a/arch/powerpc/include/asm/idle.h b/arch/powerpc/include/asm/idle.h
index b90d75a..0efb250 100644
--- a/arch/powerpc/include/asm/idle.h
+++ b/arch/powerpc/include/asm/idle.h
@@ -5,13 +5,20 @@
 #include <asm/paca.h>
 
 #ifdef CONFIG_PPC_PSERIES
+DECLARE_PER_CPU(u64, idle_spurr_cycles);
 DECLARE_PER_CPU(u64, idle_entry_purr_snap);
+DECLARE_PER_CPU(u64, idle_entry_spurr_snap);
 
 static inline void snapshot_purr_idle_entry(void)
 {
        *this_cpu_ptr(&idle_entry_purr_snap) = mfspr(SPRN_PURR);
 }
 
+static inline void snapshot_spurr_idle_entry(void)
+{
+       *this_cpu_ptr(&idle_entry_spurr_snap) = mfspr(SPRN_SPURR);
+}
+
 static inline void update_idle_purr_accounting(void)
 {
        u64 wait_cycles;
@@ -22,10 +29,19 @@ static inline void update_idle_purr_accounting(void)
        get_lppaca()->wait_state_cycles = cpu_to_be64(wait_cycles);
 }
 
+static inline void update_idle_spurr_accounting(void)
+{
+       u64 *idle_spurr_cycles_ptr = this_cpu_ptr(&idle_spurr_cycles);
+       u64 in_spurr = *this_cpu_ptr(&idle_entry_spurr_snap);
+
+       *idle_spurr_cycles_ptr += mfspr(SPRN_SPURR) - in_spurr;
+}
+
 static inline void pseries_idle_prolog(void)
 {
        ppc64_runlatch_off();
        snapshot_purr_idle_entry();
+       snapshot_spurr_idle_entry();
        /*
         * Indicate to the HV that we are idle. Now would be
         * a good time to find other work to dispatch.
@@ -36,6 +52,7 @@ static inline void pseries_idle_prolog(void)
 static inline void pseries_idle_epilog(void)
 {
        update_idle_purr_accounting();
+       update_idle_spurr_accounting();
        get_lppaca()->idle = 0;
        ppc64_runlatch_on();
 }
diff --git a/arch/powerpc/platforms/pseries/setup.c 
b/arch/powerpc/platforms/pseries/setup.c
index 4905c96..1b55e80 100644
--- a/arch/powerpc/platforms/pseries/setup.c
+++ b/arch/powerpc/platforms/pseries/setup.c
@@ -318,7 +318,9 @@ static int alloc_dispatch_log_kmem_cache(void)
 }
 machine_early_initcall(pseries, alloc_dispatch_log_kmem_cache);
 
+DEFINE_PER_CPU(u64, idle_spurr_cycles);
 DEFINE_PER_CPU(u64, idle_entry_purr_snap);
+DEFINE_PER_CPU(u64, idle_entry_spurr_snap);
 static void pseries_lpar_idle(void)
 {
        /*
-- 
1.9.4