integ/base/linuxptp/debian/bullseye/patches/0063-smooth-transparent-ha-switchover-configurable-pmc-update-interval.patch

From: Tara Subedi <Tara.Subedi@windriver.com>
Date: Mon Apr 28 13:12:23 2025 -0400
Subject: [PATCH 63/67] Smooth/Transparent HA Switchover - Configurable Pmc Update Interval

PTP: smooth/transparent HA switchover

Currently we have following inconsistency between linuxptp and
ptp-notification app.
1) pmc_agent.cc: PMC polling interval (PMC_UPDATE_INTERVAL of 60
	sec on pmc_agent_update)
2) ptp-notification app: 'overalltracker_context': {'holdover_seconds':
'15'}

In context of HA switchover, there is pmc polling in 60 sec interval
(pmc_agent_update uses PMC_UPDATE_INTERVAL i.e 60s ). This means when
primary ptp source lost, it would take 60 sec to switchover to secondary
clock.
On ptp-application app side, we have 'ptptracker_context': {'holdover_seconds':
15} 'overalltracker_context': {'holdover_seconds': '15'}
With this, when the selected ptp source is lost more than 15 sec, the ptp
state and overall state would go holdover and then freerun.

For smooth transition, PMC_UPDATE_INTERVAL should be << holdover_seconds.
This commit introduces configurable value for PMC_UPDATE_INTERVAL with
"phc2sys .. -p <int value [1, 3600]>", and without configuration, the
default value would be of 7 sec.

TEST PLAN:
PASS: deploy PTP with HA phy2sys parameter of "-p 60"
		or with file global parameter "pmc_update_interval_sec 60"
		stop primary ptp4l instance and check users.log to see the "timeout
		reading pmc" in 60 secs.
PASS: deploy PTP with HA Phy2sys without parameter of "-p"
		stop primary ptp4l instance and check users.log to see the "timeout
		reading pmc" in 7 secs.
		check HA switchover happens in 7 secs, and overall state won't
		change from Locked to holdover/freerun.

Story: 2011370
Task: 52061

Signed-off-by: Tara Nath Subedi <tara.subedi@windriver.com>
---
config.c    |  1 +
phc2sys.c   | 26 +++++++++++++++++++++++---
pmc_agent.c | 15 +++++----------
pmc_agent.h | 12 ++++++++----
4 files changed, 37 insertions(+), 17 deletions(-)

diff --git a/config.c b/config.c
index 249c9ca..319f825 100644
--- a/config.c
+++ b/config.c
@@ -348,6 +348,7 @@ struct config_item config_tab[] = {
 	GLOB_ITEM_INT("write_phase_mode", 0, 0, 1),
 	GLOB_ITEM_INT("default_sync", 1, 0, 1),
 	PORT_ITEM_INT("max_phc_update_skip_cnt", 120, 0, 14400),
+	GLOB_ITEM_INT("pmc_update_interval_sec", 7, 1, 3600),
 };
 
 static struct unicast_master_table *current_uc_mtab;
diff --git a/phc2sys.c b/phc2sys.c
index d89fb23..5f3e6c7 100644
--- a/phc2sys.c
+++ b/phc2sys.c
@@ -69,6 +69,7 @@
 #define HA_SCK_N_FD 1
 #define HA_SCK_BUFFER_SIZE 1024
 #define HA_SCK_FILEMODE (S_IRUSR|S_IWUSR|S_IRGRP|S_IWGRP) /*0660*/
+#define MAX_PMC_UPDATE_INTERVAL_SEC 3600 /* 1 hour */
 
 #define PORT_INDEX_TO_PORT_ID(port, index) (((((unsigned int) port) & 0xFF) << 8) | (((unsigned int) index) & 0xFF))
 #define PORT_ID_TO_PORT(id) ((((unsigned int) id) >> 8) & 0xFF)
@@ -1993,6 +1994,7 @@ static void usage(char *progname)
 		" common options:\n"
 		" -f [file]      configuration file\n"
 		" -E [pi|linreg] clock servo (pi)\n"
+		" -p [num]       PMC update interval in seconds (7)\n"
 		" -P [kp]        proportional constant (0.7)\n"
 		" -I [ki]        integration constant (0.3)\n"
 		" -S [step]      step threshold (disabled)\n"
@@ -2024,6 +2026,12 @@ int main(int argc, char *argv[])
 	int autocfg = 0, c, domain_number = 0, index, ntpshm_segment, offset;
 	int pps_fd = -1, print_level = LOG_INFO, r = -1, rt = 0;
 	int wait_sync = 0;
+	/* Note that pmc_subscribe_duration_sec has to be longer than
+	* pmc_update_interval_sec otherwise subscription will time out before it is
+	* renewed.
+	*/
+	int pmc_update_interval_sec = 7;
+	int pmc_subscribe_duration_sec = 3 * pmc_update_interval_sec;
 	struct clock *src, *dst;
 	struct config *cfg;
 	struct option *opts;
@@ -2062,7 +2070,7 @@ int main(int argc, char *argv[])
 	progname = strrchr(argv[0], '/');
 	progname = progname ? 1+progname : argv[0];
 	while (EOF != (c = getopt_long(argc, argv,
-				"arc:d:f:s:E:P:I:S:F:R:N:O:L:M:D:i:u:wn:xz:l:t:mqvh",
+				"arc:d:f:s:E:p:P:I:S:F:R:N:O:L:M:D:i:u:wn:xz:l:t:mqvh",
 				opts, &index))) {
 		switch (c) {
 		case 0:
@@ -2117,6 +2125,12 @@ int main(int argc, char *argv[])
 				goto end;
 			}
 			break;
+		case 'p':
+			if (get_arg_val_i(c, optarg, &pmc_update_interval_sec, 1, MAX_PMC_UPDATE_INTERVAL_SEC) ||
+				config_set_int(cfg, "pmc_update_interval_sec", pmc_update_interval_sec)) {
+				goto end;
+			}
+			break;
 		case 'P':
 			if (get_arg_val_d(c, optarg, &tmp, 0.0, DBL_MAX) ||
 			    config_set_double(cfg, "pi_proportional_const", tmp))
@@ -2289,10 +2303,15 @@ int main(int argc, char *argv[])
 	snprintf(uds_local, sizeof(uds_local), "/var/run/phc2sys.%d",
 		 getpid());
 
+	pmc_update_interval_sec = config_get_int(cfg, NULL, "pmc_update_interval_sec");
+	pmc_subscribe_duration_sec = 3 * pmc_update_interval_sec;
+	pr_info("pmc_update_interval_sec %d, pmc_subscribe_duration_sec %d",
+			pmc_update_interval_sec, pmc_subscribe_duration_sec);
 	if (autocfg) {
 		domain_number = config_get_int(cfg, NULL, "domainNumber");
 		if (init_pmc_node(cfg, node, uds_local, domain_number,
-				  phc2sys_recv_subscribed, &priv))
+				  phc2sys_recv_subscribed, &priv, pmc_update_interval_sec,
+				  pmc_subscribe_duration_sec))
 			goto end;
 		if (auto_init_ports(&priv, rt) < 0)
 			goto end;
@@ -2376,7 +2395,8 @@ int main(int argc, char *argv[])
 				domain_number = config_get_int(cfg, NULL, "domainNumber");
 			}
 			if (init_pmc_node(cfg, src->node, uds_local, domain_number,
-					phc2sys_recv_subscribed, &priv))
+					phc2sys_recv_subscribed, &priv, pmc_update_interval_sec,
+					pmc_subscribe_duration_sec))
 				goto end;
 
 			while (is_running()) {
diff --git a/pmc_agent.c b/pmc_agent.c
index 7b25e01..64012f8 100644
--- a/pmc_agent.c
+++ b/pmc_agent.c
@@ -27,19 +27,12 @@
 #include "print.h"
 #include "util.h"
 
-#define PMC_UPDATE_INTERVAL (60 * NS_PER_SEC)
-#define PMC_SUBSCRIBE_DURATION 180	/* 3 minutes */
-/* Note that PMC_SUBSCRIBE_DURATION has to be longer than
- * PMC_UPDATE_INTERVAL otherwise subscription will time out before it is
- * renewed.
- */
-
 static void send_subscription(struct pmc_agent *node)
 {
 	struct subscribe_events_np sen;
 
 	memset(&sen, 0, sizeof(sen));
-	sen.duration = PMC_SUBSCRIBE_DURATION;
+	sen.duration = node->pmc_subscribe_duration_sec;
 	event_bitmask_set(sen.bitmask, NOTIFY_PORT_STATE, TRUE);
 	pmc_send_set_action(node->pmc, MID_SUBSCRIBE_EVENTS_NP, &sen, sizeof(sen));
 }
@@ -221,7 +214,7 @@ void run_pmc_events(struct pmc_agent *node)
 
 int init_pmc_node(struct config *cfg, struct pmc_agent *node, const char *uds,
 		  int domain_number, pmc_node_recv_subscribed_t *recv_subscribed,
-		  void *context)
+		  void *context, int pmc_update_interval_sec, int pmc_subscribe_duration_sec)
 {
 	node->pmc = pmc_create(cfg, TRANS_UDS, uds, 0, domain_number,
 			       config_get_int(cfg, NULL, "transportSpecific") << 4, 1);
@@ -231,6 +224,8 @@ int init_pmc_node(struct config *cfg, struct pmc_agent *node, const char *uds,
 	}
 	node->recv_subscribed = recv_subscribed;
 	node->recv_context = context;
+	node->pmc_update_interval_sec = pmc_update_interval_sec;
+	node->pmc_subscribe_duration_sec = pmc_subscribe_duration_sec;
 
 	return 0;
 }
@@ -497,7 +492,7 @@ int pmc_agent_update(struct pmc_agent *node)
 	}
 	ts = tp.tv_sec * NS_PER_SEC + tp.tv_nsec;
 
-	if (ts - node->pmc_last_update >= PMC_UPDATE_INTERVAL) {
+	if (ts - node->pmc_last_update >= (uint64_t)node->pmc_update_interval_sec * NS_PER_SEC) {
 		if (node->stay_subscribed) {
 			renew_subscription(node, 0);
 		}
diff --git a/pmc_agent.h b/pmc_agent.h
index 4e70606..9fbe780 100644
--- a/pmc_agent.h
+++ b/pmc_agent.h
@@ -51,6 +51,9 @@ struct pmc_agent {
 	bool pds_valid;
 	bool new_pds;
 
+	int pmc_update_interval_sec;
+	int pmc_subscribe_duration_sec;
+
 	/* Callback on message reception */
 	pmc_node_recv_subscribed_t *recv_subscribed;
 	void *recv_context;
@@ -58,7 +61,7 @@ struct pmc_agent {
 
 int init_pmc_node(struct config *cfg, struct pmc_agent *agent, const char *uds,
 		  int domain_number, pmc_node_recv_subscribed_t *recv_subscribed,
-		  void *context);
+		  void *context, int pmc_update_interval_sec, int pmc_subscribe_duration_sec);
 int run_pmc_wait_sync(struct pmc_agent *agent, int timeout);
 void run_pmc_events(struct pmc_agent *agent);
 
@@ -187,10 +190,11 @@ int pmc_agent_subscribe(struct pmc_agent *agent, int timeout);
  * - The port state notification callback might be invoked.
  *
  * This function should be called periodically at least once per
- * minute to keep both the port state and the leap second flags up to
+ * 7s (configurable on agent->pmc_update_interval_sec) to keep both the
+ * port state and the leap second flags up to
  * date.  Note that the PMC agent rate limits the query to once per
- * minute, and so the caller may safely invoke this method more often
- * than that.
+ * 7s (configurable on agent->pmc_update_interval_sec), and so the caller
+ * may safely invoke this method more often than that.
  *
  * @param agent  Pointer to a PMC instance obtained via @ref pmc_agent_create().
  * @return       Zero on success, negative error code otherwise.