From 0221da5f56353c9b238ef51d5a24802ba67b8c56 Mon Sep 17 00:00:00 2001
From: Sebastian Huber <sebastian.huber@embedded-brains.de>
Date: Tue, 12 Oct 2021 08:26:39 +0200
Subject: rtems: Fix rate monotonic statistics

The rate monotonic period statistics were affected by
rtems_cpu_usage_reset().  The logic to detect and work around a CPU
usage reset was broken.

The Thread_Contol::cpu_time_used is changed to contain the processor
time used throughout the entire lifetime of the thread.  The new member
Thread_Contol::cpu_time_used_at_last_reset is added to contain the
processor time used at the time of the last reset through
rtems_cpu_usage_reset().  This decouples the resets of the CPU usage and
the rate monotonic period statistics.

Update #4528.
---
 cpukit/rtems/src/ratemongetstatus.c | 28 ++++++++++------------------
 cpukit/rtems/src/ratemonperiod.c    | 21 ++++-----------------
 2 files changed, 14 insertions(+), 35 deletions(-)

(limited to 'cpukit/rtems')

diff --git a/cpukit/rtems/src/ratemongetstatus.c b/cpukit/rtems/src/ratemongetstatus.c
index 745b52f026..5b46a7a435 100644
--- a/cpukit/rtems/src/ratemongetstatus.c
+++ b/cpukit/rtems/src/ratemongetstatus.c
@@ -31,7 +31,6 @@ rtems_status_code rtems_rate_monotonic_get_status(
 {
   Rate_monotonic_Control *the_period;
   ISR_lock_Context        lock_context;
-  rtems_status_code       status;
 
   if ( period_status == NULL ) {
     return RTEMS_INVALID_ADDRESS;
@@ -54,35 +53,28 @@ rtems_status_code rtems_rate_monotonic_get_status(
      */
     _Timespec_Set_to_zero( &period_status->since_last_period );
     _Timespec_Set_to_zero( &period_status->executed_since_last_period );
-    status = RTEMS_SUCCESSFUL;
   } else {
     Timestamp_Control wall_since_last_period;
     Timestamp_Control cpu_since_last_period;
-    bool              valid_status;
 
     /*
      *  Grab the current status.
      */
-    valid_status = _Rate_monotonic_Get_status(
+    _Rate_monotonic_Get_status(
       the_period,
       &wall_since_last_period,
       &cpu_since_last_period
     );
-    if ( valid_status ) {
-      _Timestamp_To_timespec(
-        &wall_since_last_period,
-        &period_status->since_last_period
-      );
-      _Timestamp_To_timespec(
-        &cpu_since_last_period,
-        &period_status->executed_since_last_period
-      );
-      status = RTEMS_SUCCESSFUL;
-    } else {
-      status = RTEMS_NOT_DEFINED;
-    }
+    _Timestamp_To_timespec(
+      &wall_since_last_period,
+      &period_status->since_last_period
+    );
+    _Timestamp_To_timespec(
+      &cpu_since_last_period,
+      &period_status->executed_since_last_period
+    );
   }
 
   _Rate_monotonic_Release( the_period, &lock_context );
-  return status;
+  return RTEMS_SUCCESSFUL;
 }
diff --git a/cpukit/rtems/src/ratemonperiod.c b/cpukit/rtems/src/ratemonperiod.c
index 7f0d302583..32ac688a7f 100644
--- a/cpukit/rtems/src/ratemonperiod.c
+++ b/cpukit/rtems/src/ratemonperiod.c
@@ -26,7 +26,7 @@
 #include <rtems/score/schedulerimpl.h>
 #include <rtems/score/todimpl.h>
 
-bool _Rate_monotonic_Get_status(
+void _Rate_monotonic_Get_status(
   const Rate_monotonic_Control *the_period,
   Timestamp_Control            *wall_since_last_period,
   Timestamp_Control            *cpu_since_last_period
@@ -47,14 +47,7 @@ bool _Rate_monotonic_Get_status(
   /*
    *  Determine cpu usage since period initiated.
    */
-  _Thread_Get_CPU_time_used( owning_thread, &used );
-
-  /*
-   *  The cpu usage info was reset while executing.  Can't
-   *  determine a status.
-   */
-  if ( _Timestamp_Less_than( &used, &the_period->cpu_usage_period_initiated ) )
-    return false;
+  used = _Thread_Get_CPU_time_used( owning_thread );
 
    /* used = current cpu usage - cpu usage at start of period */
   _Timestamp_Subtract(
@@ -62,8 +55,6 @@ bool _Rate_monotonic_Get_status(
     &used,
     cpu_since_last_period
   );
-
-  return true;
 }
 
 static void _Rate_monotonic_Release_postponed_job(
@@ -130,7 +121,7 @@ void _Rate_monotonic_Restart(
    *  Set the starting point and the CPU time used for the statistics.
    */
   _TOD_Get_uptime( &the_period->time_period_initiated );
-  _Thread_Get_CPU_time_used( owner, &the_period->cpu_usage_period_initiated );
+  the_period->cpu_usage_period_initiated = _Thread_Get_CPU_time_used( owner );
 
   _Rate_monotonic_Release_job(
     the_period,
@@ -147,7 +138,6 @@ static void _Rate_monotonic_Update_statistics(
   Timestamp_Control          executed;
   Timestamp_Control          since_last_period;
   Rate_monotonic_Statistics *stats;
-  bool                       valid_status;
 
   /*
    *  Assume we are only called in states where it is appropriate
@@ -167,10 +157,7 @@ static void _Rate_monotonic_Update_statistics(
   /*
    *  Grab status for time statistics.
    */
-  valid_status =
-    _Rate_monotonic_Get_status( the_period, &since_last_period, &executed );
-  if (!valid_status)
-    return;
+  _Rate_monotonic_Get_status( the_period, &since_last_period, &executed );
 
   /*
    *  Update CPU time
-- 
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