lib: Differentiate between real and cpu bound processes

When generating SLOW_THREAD warnings let's differentiate between
a cpu bound process and a wall bound process.  Effectively
a slow thread can now be a process in FRR doing lots of work( cpu bound )
or wall bound ( the cpu is heavy load and a FRR process may be pre-empted
and never scheduled ).

Signed-off-by: Donald Sharp <sharpd@nvidia.com>

4 files changed, 38 insertions, 11 deletions

diff --git a/lib/lib_errors.c b/lib/lib_errors.c
index 6e5088142..17695e660 100644
--- a/lib/lib_errors.c
+++ b/lib/lib_errors.c
@@ -45,9 +45,15 @@ static struct log_ref ferr_lib_warn[] = {
 		.suggestion = "Gather log data and open an Issue. restart FRR",
 	},
 	{
-		.code = EC_LIB_SLOW_THREAD,
-		.title = "The Event subsystem has detected a slow process",
-		.description = "The Event subsystem has detected a slow process, this typically indicates that FRR is having trouble completing work in a timely manner.  This can be either a misconfiguration, bug, or some combination therof.",
+		.code = EC_LIB_SLOW_THREAD_CPU,
+		.title = "The Event subsystem has detected a slow cpu time process",
+		.description = "The Event subsystem has detected a slow process, this typically indicates that FRR is having trouble completing work in a timely manner.  This can be either a misconfiguration, bug, or some combination therof.  In this case total CPU time was over 5 seconds.  Which indicates that FRR is very busy doing some work and should be addressed",
+		.suggestion = "Gather log data and open an Issue",
+	},
+	{
+		.code = EC_LIB_SLOW_THREAD_WALL,
+		.title = "The Event subsystem has detected a slow wall time process",
+		.description = "The Event subsystem has detected a slow process, this typically indicates that FRR is having trouble completing work in a timely manner.  This can be either a misconfiguration, bug or some combination therof.  In this case total WALL time was over 5 seconds.  Which indicates that FRR might be having trouble being scheduled or some system call is delaying",
 		.suggestion = "Gather log data and open an Issue",
 	},
 	{
diff --git a/lib/lib_errors.h b/lib/lib_errors.h
index 4730b6aa3..9f0f58d20 100644
--- a/lib/lib_errors.h
+++ b/lib/lib_errors.h
@@ -44,7 +44,8 @@ enum lib_log_refs {
 	EC_LIB_SNMP,
 	EC_LIB_STREAM,
 	EC_LIB_LINUX_NS,
-	EC_LIB_SLOW_THREAD,
+	EC_LIB_SLOW_THREAD_CPU,
+	EC_LIB_SLOW_THREAD_WALL,
 	EC_LIB_NO_THREAD,
 	EC_LIB_RMAP_RECURSION_LIMIT,
 	EC_LIB_BACKUP_CONFIG,
diff --git a/lib/thread.c b/lib/thread.c
index 866090341..7a3d50419 100644
--- a/lib/thread.c
+++ b/lib/thread.c
@@ -1850,15 +1850,29 @@ void thread_call(struct thread *thread)
 				 memory_order_seq_cst);
 
 #ifdef CONSUMED_TIME_CHECK
-	if (realtime > CONSUMED_TIME_CHECK) {
+	if (cputime > CONSUMED_TIME_CHECK) {
 		/*
-		 * We have a CPU Hog on our hands.
+		 * We have a CPU Hog on our hands.  The time FRR
+		 * has spent doing actual work ( not sleeping )
+		 * is greater than 5 seconds.
 		 * Whinge about it now, so we're aware this is yet another task
 		 * to fix.
 		 */
 		flog_warn(
-			EC_LIB_SLOW_THREAD,
-			"SLOW THREAD: task %s (%lx) ran for %lums (cpu time %lums)",
+			EC_LIB_SLOW_THREAD_CPU,
+			"CPU HOG: task %s (%lx) ran for %lums (cpu time %lums)",
+			thread->xref->funcname, (unsigned long)thread->func,
+			realtime / 1000, cputime / 1000);
+	} else if (realtime > CONSUMED_TIME_CHECK) {
+		/*
+		 * The runtime for a task is greater than 5 seconds, but
+		 * the cpu time is under 5 seconds.  Let's whine
+		 * about this because this could imply some sort of
+		 * scheduling issue.
+		 */
+		flog_warn(
+			EC_LIB_SLOW_THREAD_WALL,
+			"STARVATION: task %s (%lx) ran for %lums (cpu time %lums)",
 			thread->xref->funcname, (unsigned long)thread->func,
 			realtime / 1000, cputime / 1000);
 	}
diff --git a/lib/vty.c b/lib/vty.c
index d44cc904c..05e495c45 100644
--- a/lib/vty.c
+++ b/lib/vty.c
@@ -512,13 +512,19 @@ static int vty_command(struct vty *vty, char *buf)
 
 #ifdef CONSUMED_TIME_CHECK
 		GETRUSAGE(&after);
-		if ((realtime = thread_consumed_time(&after, &before, &cputime))
-		    > CONSUMED_TIME_CHECK)
+		realtime = thread_consumed_time(&after, &before, &cputime);
+		if (cputime > CONSUMED_TIME_CHECK) {
 			/* Warn about CPU hog that must be fixed. */
 			flog_warn(
-				EC_LIB_SLOW_THREAD,
+				EC_LIB_SLOW_THREAD_CPU,
 				"SLOW COMMAND: command took %lums (cpu time %lums): %s",
 				realtime / 1000, cputime / 1000, buf);
+		} else if (realtime > CONSUMED_TIME_CHECK) {
+			flog_warn(
+				EC_LIB_SLOW_THREAD_WALL,
+				"SLOW COMMAND: command took %lums (cpu time %lums): %s",
+				realtime / 1000, cputime / 1000, buf);
+		}
 	}
 #endif /* CONSUMED_TIME_CHECK */