騰訊GT的流暢度測試方案研究

GT源碼：https://github.com/TencentOpen/GT

一.流暢度模塊的代碼結構

流暢度插件總共就幾個類，其實處理方式也比較簡單粗暴，就是通過Choreographer輸出的log信息獲取跳幀數據。SMActivity.java為插件的入口類，你可以通過預設環境操作來實現log打印操作，然后通過SMLogService.java過濾出當前進程的丟幀值，最后由SMServiceHelper.java來進行數據處理。流暢度值為60減去1s內的跳幀數。

二.流暢度測試

1.簡要流程

• 執行setprop debug.choreographer.skipwarning 1
• 執行getprop debug.choreographer.skipwarning判斷，為1則可以進行測試
• 執行adb logcat -v time -s Choreographer:I *:S
• 過濾獲取當前pid丟幀值
• 數據處理得到sm值
  
  

2.代碼流程

• 執行setprop debug.choreographer.skipwarning 1

  View.OnClickListener button_write_property = new View.OnClickListener() {
   
          @Override
          public void onClick(View v) {
              String cmd = "setprop debug.choreographer.skipwarning 1";
              ProcessBuilder execBuilder = new ProcessBuilder("su", "-c", cmd);
              execBuilder.redirectErrorStream(true);
              try {
                  execBuilder.start();
              } catch (IOException e) {
                  e.printStackTrace();
              }
          }
      };

• 執行getprop debug.choreographer.skipwarning判斷，為1則可以進行測試

  View.OnClickListener button_check_status = new View.OnClickListener() {
   
          @Override
          public void onClick(View v) {
              String cmd = "getprop debug.choreographer.skipwarning";
              ProcessBuilder execBuilder = new ProcessBuilder("sh", "-c", cmd);
              execBuilder.redirectErrorStream(true);
              try {
                  TextView textview = (TextView) findViewById(R.id.textviewInformation);
                  Process p = execBuilder.start();
                  InputStream is = p.getInputStream();
                  InputStreamReader isr = new InputStreamReader(is);
                  BufferedReader br = new BufferedReader(isr);
                  Boolean flag = false;
                  String line;
                  while ((line = br.readLine()) != null) {
                      if (line.compareTo("1") == 0) {
                          flag = true;
                          break;
                      }
                  }
   
                  if (flag) {
                      textview.setText("OK");
                  } else {
                      textview.setText("NOT OK");
                  }
              } catch (IOException e) {
                  e.printStackTrace();
              }
          }
      };

• 執行adb logcat -v time -s Choreographer:I *:S

• 過濾獲取當前pid丟幀值

  protected void onHandleIntent(Intent intent) {
          try {
   
              String str = intent.getStringExtra("pid");
              int pid = Integer.parseInt(str);
   
              List<String> args = new ArrayList<String>(Arrays.asList("logcat", "-v", "time", "Choreographer:I", "*:S"));
   
              dumpLogcatProcess = RuntimeHelper.exec(args);
              reader = new BufferedReader(new InputStreamReader(dumpLogcatProcess.getInputStream()), 8192);
   
              String line;
   
              while ((line = reader.readLine()) != null && !killed) {
   
                  // filter "The application may be doing too much work on its main thread."
                  if (!line.contains("uch work on its main t")) {
                      continue;
                  }
                  int pID = LogLine.newLogLine(line, false).getProcessId();
                  if (pID != pid){
                      continue;
                  }
   
                  line = line.substring(50, line.length() - 71);
                  Integer value = Integer.parseInt(line.trim());
   
                  SMServiceHelper.getInstance().dataQueue.offer(value);
              }
          } catch (IOException e) {
              Log.e(TAG, e.toString() + "unexpected exception");
          } finally {
              killProcess();
          }
      }

   

• 數據處理得到sm值

   騰訊這邊的處理方案是：當丟幀<60時，流暢度SM =60-frame； 當丟幀frame>60時，流暢度SM = 60-frame%60。不過這種處理方式是有問題的。在這里要先說下流暢度計算的原理：

　　　VSync機制可以通過其Loop來了解當前App最高繪制能力，固定每隔16.6ms執行一次，這樣最高的刷新的幀率就控制在60FPS以內，Choreographer日志可以打印當前丟幀數，因此通過計算，得到當前APP的流暢度。

        而計算這樣來計算可能會更加准確：

        SM= 60-丟幀frame/每兩行同一線程的丟幀時間差（單位：s），如果只關心UI線程，那就只需要統計UI線程即可。

• while (true) {
      if (pause) {
          break;
      }
      int x = count.getAndSet(0);
      // 卡頓大於60時，要將之前幾次SM計數做修正
      if (x > 60) {
          int n = x / 60;
          int v = x % 60;
          TagTimeEntry tte = OpPerfBridge.getProfilerData(key);
          int len = tte.getRecordSize();
          // 補償參數
          int p = n;
          //Math.min(len, n);
          /*
          * n > len是剛啟動測試的情況，日志中的亡靈作祟，這種情況不做補償;
          * 並且本次也記為60。本邏輯在兩次測試間會清理數據的情況生效。
          */
          if (n > len) {
              globalClient.setOutPara(key, 60);
  //          globalClient.setOutPara(SFKey, 0);
          } else {
              for (int i = 0; i < p; i++) {
              TimeEntry te = tte.getRecord(len - 1 - i);
              te.reduce = 0;
              }
          globalClient.setOutPara(key, v);
  //      globalClient.setOutPara(SFKey, 60 - v);
          }
      } else {
          int sm = 60 - x;
          globalClient.setOutPara(key, sm);
  //      globalClient.setOutPara(SFKey, x);
      }