Add two timestamps to measure PSCI cache flush overhead
Testing showed that the time spent in a cluster power down
operation is dominated by cache flushes. Add two more timestamps
in runtime instrumentation to keep track of the time spent
flushing the L1/L2 caches.
Change-Id: I4c5a04e7663543225a85d3c6b271d7b706deffc4
Signed-off-by: dp-arm <dimitris.papastamos@arm.com>
diff --git a/include/lib/runtime_instr.h b/include/lib/runtime_instr.h
index d409002..4d05ba4 100644
--- a/include/lib/runtime_instr.h
+++ b/include/lib/runtime_instr.h
@@ -31,11 +31,13 @@
#ifndef __RUNTIME_INSTR_H__
#define __RUNTIME_INSTR_H__
-#define RT_INSTR_TOTAL_IDS 4
#define RT_INSTR_ENTER_PSCI 0
#define RT_INSTR_EXIT_PSCI 1
#define RT_INSTR_ENTER_HW_LOW_PWR 2
#define RT_INSTR_EXIT_HW_LOW_PWR 3
+#define RT_INSTR_ENTER_CFLUSH 4
+#define RT_INSTR_EXIT_CFLUSH 5
+#define RT_INSTR_TOTAL_IDS 6
#ifndef __ASSEMBLY__
PMF_DECLARE_CAPTURE_TIMESTAMP(rt_instr_svc)
diff --git a/lib/psci/psci_off.c b/lib/psci/psci_off.c
index 1cc6ede..897bf31 100644
--- a/lib/psci/psci_off.c
+++ b/lib/psci/psci_off.c
@@ -107,12 +107,29 @@
psci_stats_update_pwr_down(end_pwrlvl, &state_info);
#endif
+#if ENABLE_RUNTIME_INSTRUMENTATION
+
+ /*
+ * Flush cache line so that even if CPU power down happens
+ * the timestamp update is reflected in memory.
+ */
+ PMF_CAPTURE_TIMESTAMP(rt_instr_svc,
+ RT_INSTR_ENTER_CFLUSH,
+ PMF_CACHE_MAINT);
+#endif
+
/*
* Arch. management. Perform the necessary steps to flush all
* cpu caches.
*/
psci_do_pwrdown_cache_maintenance(psci_find_max_off_lvl(&state_info));
+#if ENABLE_RUNTIME_INSTRUMENTATION
+ PMF_CAPTURE_TIMESTAMP(rt_instr_svc,
+ RT_INSTR_EXIT_CFLUSH,
+ PMF_NO_CACHE_MAINT);
+#endif
+
/*
* Plat. management: Perform platform specific actions to turn this
* cpu off e.g. exit cpu coherency, program the power controller etc.
diff --git a/lib/psci/psci_suspend.c b/lib/psci/psci_suspend.c
index 10d2481..dc2ab77 100644
--- a/lib/psci/psci_suspend.c
+++ b/lib/psci/psci_suspend.c
@@ -109,6 +109,17 @@
*/
cm_init_my_context(ep);
+#if ENABLE_RUNTIME_INSTRUMENTATION
+
+ /*
+ * Flush cache line so that even if CPU power down happens
+ * the timestamp update is reflected in memory.
+ */
+ PMF_CAPTURE_TIMESTAMP(rt_instr_svc,
+ RT_INSTR_ENTER_CFLUSH,
+ PMF_CACHE_MAINT);
+#endif
+
/*
* Arch. management. Perform the necessary steps to flush all
* cpu caches. Currently we assume that the power level correspond
@@ -117,6 +128,12 @@
* and the cpu-ops power down to perform from the platform.
*/
psci_do_pwrdown_cache_maintenance(max_off_lvl);
+
+#if ENABLE_RUNTIME_INSTRUMENTATION
+ PMF_CAPTURE_TIMESTAMP(rt_instr_svc,
+ RT_INSTR_EXIT_CFLUSH,
+ PMF_NO_CACHE_MAINT);
+#endif
}
/*******************************************************************************
