Cosmetic changes to load.c, load.h. Adds and cleans up comments.

[can-benchmark.git] / rtems / gw / libs / load.c

diff --git a/rtems/gw/libs/load.c b/rtems/gw/libs/load.c
index ba7fac4c67f761197e072d054f98c4e9745319ff..6afb7a9f5ddf806e394bc4e806a035d40ee727c9 100644 (file)
--- a/rtems/gw/libs/load.c
+++ b/rtems/gw/libs/load.c
@@ -1,11 +1,3 @@
-/*\r
-* Implements simple producer/consumer thread pair to cause load on the CPU.\r
-* \r
-* Used in benchmarking the CAN gateway.\r
-*\r
-* Co-opted from http://support.dce.felk.cvut.cz/pos/cv3/src/semaphore.html. \r
-*/\r
-\r
 #include <stdio.h>\r
 \r
 #include <pthread.h>\r
@@ -13,7 +5,7 @@
 \r
 #include "load.h"\r
 \r
-\r
+/* Load function for threads. */\r
 static void* produce(void* arg);\r
 static void* consume(void* arg);\r
 \r
@@ -27,7 +19,7 @@ static char running = 0;
 static void* produce(void* arg){\r
     while (1) {\r
             sem_wait(&consumed);\r
-            n++;  /* increment n by 1 */\r
+            n++; \r
             sem_post(&produced);\r
             pthread_testcancel();\r
     }\r
@@ -37,13 +29,20 @@ static void* produce(void* arg){
 static void* consume(void* arg){\r
     while (1) {\r
             sem_wait(&produced);\r
-            n--; /* aaand decrement */\r
+            n--;\r
             sem_post(&consumed);\r
             pthread_testcancel();\r
     }\r
     return NULL;\r
 }\r
 \r
+/*\r
+* This function starts threads loading the CPU and creates associated semaphores. \r
+* \r
+* Has a guard to prevent starting again, before it was stopped.\r
+*\r
+* No error handling currently, only tries to report errors.\r
+*/\r
 int start_thread_load(){\r
     if (running == 0){\r
         printf("Attempting to start load.\n");\r
@@ -84,9 +83,10 @@ int start_thread_load(){
 \r
 /*\r
 * This function stops threads loading the CPU and destroys associated semaphores. \r
+*\r
+* Has a guard against attempting to stop the threads if they are not running.\r
 * \r
 * No error handling currently, only tries to report errors.\r
-* \r
 */\r
 int end_thread_load(){\r
     if (running == 1){\r
@@ -94,15 +94,22 @@ int end_thread_load(){
         printf("Attempting to cancel producer thread.\n");\r
         res = pthread_cancel(producer);\r
         if (res != 0){\r
+            /* This means that sending cancel signal has failed... Just returning an error should be enough. */\r
+            /* If we killed the thread, destroying the semaphore would lead to UB. */\r
             printf("Failed.\n");\r
-            /* Not sure what to do with error here, will have to figure out later. */\r
+            return 1;\r
         }\r
+\r
         printf("Attempting to cancel consumer thread.\n");\r
         res = pthread_cancel(consumer);\r
         if (res != 0){\r
+            /* Same here. */\r
             printf("Failed.\n");\r
+            return 1;\r
         }\r
+\r
         printf("Preparing to destroy semaphores.\n");\r
+        /* Wait a bit so that the threads can get to a cancellation point. */\r
         sleep(1);\r
         sem_destroy(&produced);\r
         sem_destroy(&consumed);\r