Revision 0:a88acbffd78b, committed 2017-10-23

Comitter:

deepikabhavnani

Date:

Mon Oct 23 21:11:16 2017 +0000

Commit message:

CriticalSection API example

Changed in this revision

diff -r 000000000000 -r a88acbffd78b .gitignore
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/.gitignore	Mon Oct 23 21:11:16 2017 +0000
@@ -0,0 +1,4 @@
+.build
+.mbed
+projectfiles
+*.py*

diff -r 000000000000 -r a88acbffd78b README.md
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/README.md	Mon Oct 23 21:11:16 2017 +0000
@@ -0,0 +1,8 @@
+    
+### Getting started with the CriticalSectionLock API ###
+ 
+CriticalSectionLock Example
+This application demonstrated race condition when multiple threads update
+global shared resource.CriticalSectionLock is used to avoid this race condition 
+and protect the shared counter. 
+ 
\ No newline at end of file

diff -r 000000000000 -r a88acbffd78b img/uvision.png
Binary file img/uvision.png has changed

diff -r 000000000000 -r a88acbffd78b main.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp	Mon Oct 23 21:11:16 2017 +0000
@@ -0,0 +1,61 @@
+/*
+ * Copyright (c) 2016-2016, ARM Limited, All Rights Reserved
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#include "rtos/Thread.h"
+#include "mbed.h"
+#include "rtos/rtos_idle.h"
+#include "platform/mbed_critical.h"
+ 
+#define  USE_CRITICAL_SECTION_LOCK      1   // Set 0 to see race condition
+// Note: Might require few runs to see race condition
+ 
+#define THREAD_CNT  8
+ 
+int32_t value = 100000;
+volatile int32_t count = 0;
+ 
+void increment(void) {
+    for (int i = 0; i < value; i++) {
+#if (USE_CRITICAL_SECTION_LOCK == 1)
+        CriticalSectionLock  lock;
+#endif
+        count += 1;
+    }
+}
+ 
+int get_count(void) {
+    if (count == (value * THREAD_CNT)) {
+        printf("No Race condition\n");
+    } else {
+        printf("Race condition\n");
+    }
+    return count;
+}
+ 
+int main()
+{
+    Thread counter_thread[THREAD_CNT];    
+ 
+    for (int i = 0; i < THREAD_CNT; i++) {
+        counter_thread[i].start(callback(increment));
+    }
+    
+    // Wait for the threads to finish
+    for (int i = 0; i < THREAD_CNT; i++) {
+        counter_thread[i].join();
+    }    
+    printf ("Counter = %d\n", get_count());
+}

diff -r 000000000000 -r a88acbffd78b mbed-os.lib
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mbed-os.lib	Mon Oct 23 21:11:16 2017 +0000
@@ -0,0 +1,1 @@
+https://github.com/ARMmbed/mbed-os/#6e0d01cd13e8aca7bf4d697c3699ec9225386881