com.xiaomi.infra.galaxy.talos.client.ThrottleUtils Maven / Gradle / Ivy
/**
* Copyright 2015, Xiaomi.
* All rights reserved.
* Author: [email protected]
*/
package com.xiaomi.infra.galaxy.talos.client;
import java.util.Random;
import com.xiaomi.infra.galaxy.talos.thrift.CommonConstants;
import com.xiaomi.infra.galaxy.talos.thrift.ErrorCode;
public class ThrottleUtils {
private static final Random RANDOM = new Random();
/**
* This is a retry backoff multiplier table similar to the BSD TCP syn
* backoff table, a bit more aggressive than simple exponential backoff.
*/
public static int RETRY_BACKOFF[] = { 1, 4, 8, 16, 32, 64 };
/**
* Calculate random time with 1% possible jitter
* @param normalPause
* @return random time value
*/
private static long getRandom(final long normalPause) {
long jitter = (long)(normalPause * RANDOM.nextFloat() * 0.10f); // 10% possible jitter
return normalPause + jitter;
}
/**
* Calculate pause time.
* Built on {@link #RETRY_BACKOFF}.
* @param pause
* @param tries
* @return How long to wait after tries retries
*/
private static long getBackoffTime(final long pause, final int tries) {
int ntries = tries;
if (ntries >= RETRY_BACKOFF.length) {
ntries = RETRY_BACKOFF.length - 1;
}
long normalPause = pause * RETRY_BACKOFF[ntries];
return getRandom(normalPause);
}
/**
* Calculate pause time based on multiplicative decrease back-off policy
* @param code
* @param retry
* @return time to pause
*/
public static long getPauseTime(ErrorCode code, int retry) {
Long time = CommonConstants.ERROR_BACKOFF.get(code);
if (time == null) {
return -1;
}
return getBackoffTime(time, retry);
}
/**
* Calculate pause time based on additive increase back-off policy
* @return time to pause
*/
public static long getPauseTime(long lastPauseTime) {
if (lastPauseTime == 0) {
return 0;
}
// decrease time with the larger of (the last pause time * 20%) and 200
long pauseTime = lastPauseTime - getRandom(Math.max((long) (lastPauseTime * 0.2), 200));
pauseTime = pauseTime < 0 ? 0 : pauseTime;
return pauseTime;
}
public static void sleepPauseTime(long pauseTime) {
if (pauseTime > 0) {
try {
Thread.sleep(pauseTime);
} catch (InterruptedException ie) {
throw new RuntimeException("thread sleep failed", ie);
}
}
}
}