[PATCH v1 3/3] examples/l3fwd-power: enable PMD power mgmt on Arm

[Feifei Wang <feifei.wang2@arm.com>]

For Arm aarch, power monitor uses WFE instruction to enable, which can
not exit automatically within the time limit. This means
'rte_power_monitor_wakeup' API needs to be called to wake up sleep cores
if there is no store operation to monitored address.

Furthermore, we disable power monitor feature on the main core so that it
can be used to wake up other sleeping cores when it receives SIGINT
siginal.

Signed-off-by: Feifei Wang <feifei.wang2@arm.com>
Reviewed-by: Ruifeng Wang <ruifeng.wang@arm.com>
---
 examples/l3fwd-power/main.c | 30 +++++++++++++++++++++++++++++-
 1 file changed, 29 insertions(+), 1 deletion(-)

diff --git a/examples/l3fwd-power/main.c b/examples/l3fwd-power/main.c
index 887c6eae3f..2bd0d700f0 100644
--- a/examples/l3fwd-power/main.c
+++ b/examples/l3fwd-power/main.c
@@ -432,8 +432,16 @@ static void
 signal_exit_now(int sigtype)
 {
 
-	if (sigtype == SIGINT)
+	if (sigtype == SIGINT) {
+#if defined(RTE_ARCH_ARM64)
+	/**
+	 * wake_up api does not need input parameter on Arm,
+	 * so 0 is meaningless here.
+	 */
+		rte_power_monitor_wakeup(0);
+#endif
 		quit_signal = true;
+	}
 
 }
 
@@ -2885,6 +2893,25 @@ main(int argc, char **argv)
 						"Error setting scaling freq max: err=%d, lcore %d\n",
 							ret, lcore_id);
 
+#if defined(RTE_ARCH_ARM64)
+				/* Ensure the main lcore does not enter the power-monitor state,
+				 * so that it can be used to wake up other lcores on ARM.
+				 * This is due to WFE instruction has no timeout wake-up mechanism,
+				 * and if users want to exit actively, the main lcore is needed
+				 * to send SEV instruction to wake up other lcores.
+				 */
+				unsigned int main_lcore = rte_get_main_lcore();
+				if (lcore_id != main_lcore ||
+						pmgmt_type != RTE_POWER_MGMT_TYPE_MONITOR) {
+					ret = rte_power_ethdev_pmgmt_queue_enable(
+							lcore_id, portid, queueid,
+							pmgmt_type);
+					if (ret < 0)
+						rte_exit(EXIT_FAILURE,
+							"rte_power_ethdev_pmgmt_queue_enable: err=%d, port=%d\n",
+							ret, portid);
+				}
+#else
 				ret = rte_power_ethdev_pmgmt_queue_enable(
 						lcore_id, portid, queueid,
 						pmgmt_type);
@@ -2892,6 +2919,7 @@ main(int argc, char **argv)
 					rte_exit(EXIT_FAILURE,
 						"rte_power_ethdev_pmgmt_queue_enable: err=%d, port=%d\n",
 							ret, portid);
+#endif
 			}
 		}
 	}
-- 
2.25.1