[Solved] Efficient way to monitor tps

[AnZaNaMa]

Hello, I'm attempting to monitor the average tick time of a forge server in my mod. Currently, I'm using an event handler that subscibes to TickEvent.ServerTickEvent to record System.currentTimeMillis each tick and then when someone asks for the TPS, I average out the differences between times in the array to find the mean tick time in milliseconds and divide 1000 by that to get the TPS. However, the numbers I come up with are always much larger than those produced by the 'forge tps' command (i.e. 0.3ms vs 10ms).

 

I'm fairly certain my math is correct, which means there must be a problem with the way I am recording data each tick. Is there a better way for me to accomplish this? Below is my code:

 

@SubscribeEvent
public static void onTick(TickEvent.ServerTickEvent event) {
	StatusAPI.data.tick();
}

public static JsonObject tps() {
  long[] tickList = StatusAPI.data.getTickList();
  long totalMillis = 0;
  int endIndex = tickList[tickList.length-1] != 0 ? tickList.length : StatusAPI.data.getTickListIndex();
  for(int i=0; i < endIndex - 1; i++) {
    long diff = tickList[i+1] - tickList[i];
    totalMillis += diff;
  }
  float averageMillis = (float)totalMillis / (float)endIndex;
  float ticksPerSecond = 1000F / averageMillis;
  JsonObject data = new JsonObject();
  DecimalFormat df = new DecimalFormat("0.00");
  data.addProperty("ticksPerSecond", df.format(ticksPerSecond));
  data.addProperty("averageTickTime", df.format(averageMillis));
  return data;
}

 

Edited June 2, 2019 by AnZaNaMa

[deerangle]

Why don't you measure the time it took to complete 20 ticks, then divide 1000ms by the measured time, and multiply that number with the 20 ticks you counted.

 

long measuredTime = 2000L; //this means it took 2000ms for 20 ticks to complete
float tps = 20 * (1000f / measuredTime); // 1000/2000 = 0.5; 0.5 * 20 = 10 tps

 

To count the time 20 ticks take, create a field in your eventhandler that counts up every server tick, and when it reaches 20, you calculate the time difference between the last time it reached 20, and then reset the counter. 

 

You can effectively vary the 20 ticks and use whatever value you want. The higher the number, the slower the tps updates.

[AnZaNaMa]

I discovered that either minecraft or forge is already keeping a record of tick times, so I'll just use this instead to avoid having a tick handler that bogs down the server. For anyone in the future, who's interested in this, look in net.minecraftforge.server.command.CommandTps to see how the forge TPS command calculates it.