[dpdk-dev] [PATCH v9 7/8] power: support monitoring multiple Rx queues

[Anatoly Burakov <anatoly.burakov@intel.com>]

Use the new multi-monitor intrinsic to allow monitoring multiple ethdev
Rx queues while entering the energy efficient power state. The multi
version will be used unconditionally if supported, and the UMWAIT one
will only be used when multi-monitor is not supported by the hardware.

Signed-off-by: Anatoly Burakov <anatoly.burakov@intel.com>
Acked-by: Konstantin Ananyev <konstantin.ananyev@intel.com>
Tested-by: David Hunt <david.hunt@intel.com>
---

Notes:
    v6:
    - Fix the missed feedback from v5
    
    v4:
    - Fix possible out of bounds access
    - Added missing index increment

 doc/guides/prog_guide/power_man.rst | 15 ++++--
 lib/power/rte_power_pmd_mgmt.c      | 82 ++++++++++++++++++++++++++++-
 2 files changed, 90 insertions(+), 7 deletions(-)

diff --git a/doc/guides/prog_guide/power_man.rst b/doc/guides/prog_guide/power_man.rst
index 0e66878892..e387d7811e 100644
--- a/doc/guides/prog_guide/power_man.rst
+++ b/doc/guides/prog_guide/power_man.rst
@@ -221,17 +221,22 @@ power saving whenever empty poll count reaches a certain number.
 The "monitor" mode is only supported in the following configurations and scenarios:
 
 * On Linux* x86_64, `rte_power_monitor()` requires WAITPKG instruction set being
-  supported by the CPU. Please refer to your platform documentation for further
-  information.
+  supported by the CPU, while `rte_power_monitor_multi()` requires WAITPKG and
+  RTM instruction sets being supported by the CPU. RTM instruction set may also
+  require booting the Linux with `tsx=on` command line parameter. Please refer
+  to your platform documentation for further information.
 
 * If ``rte_cpu_get_intrinsics_support()`` function indicates that
+  ``rte_power_monitor_multi()`` function is supported by the platform, then
+  monitoring multiple Ethernet Rx queues for traffic will be supported.
+
+* If ``rte_cpu_get_intrinsics_support()`` function indicates that only
   ``rte_power_monitor()`` is supported by the platform, then monitoring will be
   limited to a mapping of 1 core 1 queue (thus, each Rx queue will have to be
   monitored from a different lcore).
 
-* If ``rte_cpu_get_intrinsics_support()`` function indicates that the
-  ``rte_power_monitor()`` function is not supported, then monitor mode will not
-  be supported.
+* If ``rte_cpu_get_intrinsics_support()`` function indicates that neither of the
+  two monitoring functions are supported, then monitor mode will not be supported.
 
 * Not all Ethernet drivers support monitoring, even if the underlying
   platform may support the necessary CPU instructions. Please refer to
diff --git a/lib/power/rte_power_pmd_mgmt.c b/lib/power/rte_power_pmd_mgmt.c
index 30772791af..2586204b93 100644
--- a/lib/power/rte_power_pmd_mgmt.c
+++ b/lib/power/rte_power_pmd_mgmt.c
@@ -126,6 +126,32 @@ queue_list_take(struct pmd_core_cfg *cfg, const union queue *q)
 	return found;
 }
 
+static inline int
+get_monitor_addresses(struct pmd_core_cfg *cfg,
+		struct rte_power_monitor_cond *pmc, size_t len)
+{
+	const struct queue_list_entry *qle;
+	size_t i = 0;
+	int ret;
+
+	TAILQ_FOREACH(qle, &cfg->head, next) {
+		const union queue *q = &qle->queue;
+		struct rte_power_monitor_cond *cur;
+
+		/* attempted out of bounds access */
+		if (i >= len) {
+			RTE_LOG(ERR, POWER, "Too many queues being monitored\n");
+			return -1;
+		}
+
+		cur = &pmc[i++];
+		ret = rte_eth_get_monitor_addr(q->portid, q->qid, cur);
+		if (ret < 0)
+			return ret;
+	}
+	return 0;
+}
+
 static void
 calc_tsc(void)
 {
@@ -215,6 +241,46 @@ lcore_can_sleep(struct pmd_core_cfg *cfg)
 	return true;
 }
 
+static uint16_t
+clb_multiwait(uint16_t port_id __rte_unused, uint16_t qidx __rte_unused,
+		struct rte_mbuf **pkts __rte_unused, uint16_t nb_rx,
+		uint16_t max_pkts __rte_unused, void *arg)
+{
+	const unsigned int lcore = rte_lcore_id();
+	struct queue_list_entry *queue_conf = arg;
+	struct pmd_core_cfg *lcore_conf;
+	const bool empty = nb_rx == 0;
+
+	lcore_conf = &lcore_cfgs[lcore];
+
+	/* early exit */
+	if (likely(!empty))
+		/* early exit */
+		queue_reset(lcore_conf, queue_conf);
+	else {
+		struct rte_power_monitor_cond pmc[lcore_conf->n_queues];
+		int ret;
+
+		/* can this queue sleep? */
+		if (!queue_can_sleep(lcore_conf, queue_conf))
+			return nb_rx;
+
+		/* can this lcore sleep? */
+		if (!lcore_can_sleep(lcore_conf))
+			return nb_rx;
+
+		/* gather all monitoring conditions */
+		ret = get_monitor_addresses(lcore_conf, pmc,
+				lcore_conf->n_queues);
+		if (ret < 0)
+			return nb_rx;
+
+		rte_power_monitor_multi(pmc, lcore_conf->n_queues, UINT64_MAX);
+	}
+
+	return nb_rx;
+}
+
 static uint16_t
 clb_umwait(uint16_t port_id, uint16_t qidx, struct rte_mbuf **pkts __rte_unused,
 		uint16_t nb_rx, uint16_t max_pkts __rte_unused, void *arg)
@@ -366,14 +432,19 @@ static int
 check_monitor(struct pmd_core_cfg *cfg, const union queue *qdata)
 {
 	struct rte_power_monitor_cond dummy;
+	bool multimonitor_supported;
 
 	/* check if rte_power_monitor is supported */
 	if (!global_data.intrinsics_support.power_monitor) {
 		RTE_LOG(DEBUG, POWER, "Monitoring intrinsics are not supported\n");
 		return -ENOTSUP;
 	}
+	/* check if multi-monitor is supported */
+	multimonitor_supported =
+			global_data.intrinsics_support.power_monitor_multi;
 
-	if (cfg->n_queues > 0) {
+	/* if we're adding a new queue, do we support multiple queues? */
+	if (cfg->n_queues > 0 && !multimonitor_supported) {
 		RTE_LOG(DEBUG, POWER, "Monitoring multiple queues is not supported\n");
 		return -ENOTSUP;
 	}
@@ -389,6 +460,13 @@ check_monitor(struct pmd_core_cfg *cfg, const union queue *qdata)
 	return 0;
 }
 
+static inline rte_rx_callback_fn
+get_monitor_callback(void)
+{
+	return global_data.intrinsics_support.power_monitor_multi ?
+		clb_multiwait : clb_umwait;
+}
+
 int
 rte_power_ethdev_pmgmt_queue_enable(unsigned int lcore_id, uint16_t port_id,
 		uint16_t queue_id, enum rte_power_pmd_mgmt_type mode)
@@ -453,7 +531,7 @@ rte_power_ethdev_pmgmt_queue_enable(unsigned int lcore_id, uint16_t port_id,
 		if (ret < 0)
 			goto end;
 
-		clb = clb_umwait;
+		clb = get_monitor_callback();
 		break;
 	case RTE_POWER_MGMT_TYPE_SCALE:
 		/* check if we can add a new queue */
-- 
2.25.1