runtime % support for FreeRTOS V11 (#57)

* runtime % support for FreeRTOS V11

In V11, FreeRTOS changed ulTotalRunTime from an integer to an array of
integers. On SMP, the array has one entry per CPU, but it's still a
one-element array even without SMP support compiled in.

Try finding the length of the array with sizeof(a)/sizeof(a[0]). If that
succeeds, sum all CPU runtimes to get the total runtime. If it fails,
assume V10 or earlier and fall back to the previous technique.

* correct FreeRTOS V11 runtime stats detection in help text generation

* simplify implementation of FreeRTOS V11 runtime % support

Convert `updateTotalRuntime()` to an async function. Use
`RTOSVarHelper.getVarChildren()` to check for the presence of children
and to get their values.

Author: malsyned

src/rtos/rtos-freertos.ts

@@ -345,22 +345,21 @@ export class RTOSFreeRTOS extends RTOSCommon.RTOSBase {
         });
     }
 
-    private updateTotalRuntime(frameId: number): Promise<void> {
-        return new Promise<void>((resolve, reject) => {
-            if (!this.ulTotalRunTime) {
-                resolve();
-                return;
+    private async updateTotalRuntime(frameId: number): Promise<void> {
+        if (!this.ulTotalRunTime) {
+            return;
+        }
+        try {
+            let total = 0;
+            const children = await this.ulTotalRunTime.getVarChildren(frameId);
+            for (const child of children) {
+                total += parseInt(child.value || '');
             }
-            this.ulTotalRunTime.getValue(frameId).then(
-                (ret) => {
-                    this.ulTotalRunTimeVal = parseInt(ret || '');
-                    resolve();
-                },
-                (e) => {
-                    reject(e);
-                }
-            );
-        });
+            this.ulTotalRunTimeVal = total;
+        } catch (e) {
+            const ret = await this.ulTotalRunTime.getValue(frameId);
+            this.ulTotalRunTimeVal = parseInt(ret || '');
+        }
     }
 
     public refresh(frameId: number): Promise<void> {