The statistic node keep three kinds of real-time statistics metrics:
*This class is usually preferable to {@link AtomicLong} when - * multiple threads update a common sum that is used for purposes such - * as collecting statistics, not for fine-grained synchronization - * control. Under low update contention, the two classes have similar - * characteristics. But under high contention, expected throughput of - * this class is significantly higher, at the expense of higher space - * consumption. - * - *
This class extends {@link Number}, but does not define - * methods such as {@code hashCode} and {@code compareTo} because - * instances are expected to be mutated, and so are not useful as - * collection keys. - * - *
jsr166e note: This class is targeted to be placed in
- * java.util.concurrent.atomic
- *
- * @author Doug Lea
- * @since 1.8
- */
-public class LongAdder extends Striped64 implements Serializable {
- private static final long serialVersionUID = 7249069246863182397L;
-
- /**
- * Version of plus for use in retryUpdate
- */
- @Override
- final long fn(long v, long x) { return v + x; }
-
- /**
- * Creates a new adder with initial sum of zero.
- */
- public LongAdder() {
- }
-
- /**
- * Adds the given value.
- *
- * @param x the value to add
- */
- public void add(long x) {
- Cell[] as;
- long b, v;
- HashCode hc;
- Cell a;
- int n;
- if ((as = cells) != null || !casBase(b = base, b + x)) {
- boolean uncontended = true;
- int h = (hc = threadHashCode.get()).code;
- if (as == null || (n = as.length) < 1 ||
- (a = as[(n - 1) & h]) == null ||
- !(uncontended = a.cas(v = a.value, v + x))) { retryUpdate(x, hc, uncontended); }
- }
- }
-
- /**
- * Equivalent to {@code add(1)}.
- */
- public void increment() {
- add(1L);
- }
-
- /**
- * Equivalent to {@code add(-1)}.
- */
- public void decrement() {
- add(-1L);
- }
-
- /**
- * Returns the current sum. The returned value is NOT an
- * atomic snapshot: Invocation in the absence of concurrent
- * updates returns an accurate result, but concurrent updates that
- * occur while the sum is being calculated might not be
- * incorporated.
- *
- * @return the sum
- */
- public long sum() {
- long sum = base;
- Cell[] as = cells;
- if (as != null) {
- int n = as.length;
- for (int i = 0; i < n; ++i) {
- Cell a = as[i];
- if (a != null) { sum += a.value; }
- }
- }
- return sum;
- }
-
- /**
- * Resets variables maintaining the sum to zero. This method may
- * be a useful alternative to creating a new adder, but is only
- * effective if there are no concurrent updates. Because this
- * method is intrinsically racy, it should only be used when it is
- * known that no threads are concurrently updating.
- */
- public void reset() {
- internalReset(0L);
- }
-
- /**
- * Equivalent in effect to {@link #sum} followed by {@link
- * #reset}. This method may apply for example during quiescent
- * points between multithreaded computations. If there are
- * updates concurrent with this method, the returned value is
- * not guaranteed to be the final value occurring before
- * the reset.
- *
- * @return the sum
- */
- public long sumThenReset() {
- long sum = base;
- Cell[] as = cells;
- base = 0L;
- if (as != null) {
- int n = as.length;
- for (int i = 0; i < n; ++i) {
- Cell a = as[i];
- if (a != null) {
- sum += a.value;
- a.value = 0L;
- }
- }
- }
- return sum;
- }
-
- /**
- * Returns the String representation of the {@link #sum}.
- *
- * @return the String representation of the {@link #sum}
- */
- @Override
- public String toString() {
- return Long.toString(sum());
- }
-
- /**
- * Equivalent to {@link #sum}.
- *
- * @return the sum
- */
- @Override
- public long longValue() {
- return sum();
- }
-
- /**
- * Returns the {@link #sum} as an {@code int} after a narrowing
- * primitive conversion.
- */
- @Override
- public int intValue() {
- return (int)sum();
- }
-
- /**
- * Returns the {@link #sum} as a {@code float}
- * after a widening primitive conversion.
- */
- @Override
- public float floatValue() {
- return (float)sum();
- }
-
- /**
- * Returns the {@link #sum} as a {@code double} after a widening
- * primitive conversion.
- */
- @Override
- public double doubleValue() {
- return (double)sum();
- }
-
- private void writeObject(java.io.ObjectOutputStream s)
- throws java.io.IOException {
- s.defaultWriteObject();
- s.writeLong(sum());
- }
-
- private void readObject(ObjectInputStream s)
- throws IOException, ClassNotFoundException {
- s.defaultReadObject();
- busy = 0;
- cells = null;
- base = s.readLong();
- }
-
-}
\ No newline at end of file
diff --git a/sentinel-core/src/main/java/com/alibaba/csp/sentinel/slots/statistic/base/Striped64.java b/sentinel-core/src/main/java/com/alibaba/csp/sentinel/slots/statistic/base/Striped64.java
deleted file mode 100755
index cab42f0a..00000000
--- a/sentinel-core/src/main/java/com/alibaba/csp/sentinel/slots/statistic/base/Striped64.java
+++ /dev/null
@@ -1,349 +0,0 @@
-
-package com.alibaba.csp.sentinel.slots.statistic.base;
-
-/*
- * Written by Doug Lea with assistance from members of JCP JSR-166
- * Expert Group and released to the public domain, as explained at
- * http://creativecommons.org/publicdomain/zero/1.0/
- *
- * From http://gee.cs.oswego.edu/cgi-bin/viewcvs.cgi/jsr166/src/jsr166e/
- */
-
-import java.util.Random;
-
-/**
- * A package-local class holding common representation and mechanics
- * for classes supporting dynamic striping on 64bit values. The class
- * extends Number so that concrete subclasses must publicly do so.
- */
-abstract class Striped64 extends Number {
- /*
- * This class maintains a lazily-initialized table of atomically
- * updated variables, plus an extra "base" field. The table size
- * is a power of two. Indexing uses masked per-thread hash codes.
- * Nearly all declarations in this class are package-private,
- * accessed directly by subclasses.
- *
- * Table entries are of class Cell; a variant of AtomicLong padded
- * to reduce cache contention on most processors. Padding is
- * overkill for most Atomics because they are usually irregularly
- * scattered in memory and thus don't interfere much with each
- * other. But Atomic objects residing in arrays will tend to be
- * placed adjacent to each other, and so will most often share
- * cache lines (with a huge negative performance impact) without
- * this precaution.
- *
- * In part because Cells are relatively large, we avoid creating
- * them until they are needed. When there is no contention, all
- * updates are made to the base field. Upon first contention (a
- * failed CAS on base update), the table is initialized to size 2.
- * The table size is doubled upon further contention until
- * reaching the nearest power of two greater than or equal to the
- * number of CPUS. Table slots remain empty (null) until they are
- * needed.
- *
- * A single spinlock ("busy") is used for initializing and
- * resizing the table, as well as populating slots with new Cells.
- * There is no need for a blocking lock: When the lock is not
- * available, threads try other slots (or the base). During these
- * retries, there is increased contention and reduced locality,
- * which is still better than alternatives.
- *
- * Per-thread hash codes are initialized to random values.
- * Contention and/or table collisions are indicated by failed
- * CASes when performing an update operation (see method
- * retryUpdate). Upon a collision, if the table size is less than
- * the capacity, it is doubled in size unless some other thread
- * holds the lock. If a hashed slot is empty, and lock is
- * available, a new Cell is created. Otherwise, if the slot
- * exists, a CAS is tried. Retries proceed by "double hashing",
- * using a secondary hash (Marsaglia XorShift) to try to find a
- * free slot.
- *
- * The table size is capped because, when there are more threads
- * than CPUs, supposing that each thread were bound to a CPU,
- * there would exist a perfect hash function mapping threads to
- * slots that eliminates collisions. When we reach capacity, we
- * search for this mapping by randomly varying the hash codes of
- * colliding threads. Because search is random, and collisions
- * only become known via CAS failures, convergence can be slow,
- * and because threads are typically not bound to CPUS forever,
- * may not occur at all. However, despite these limitations,
- * observed contention rates are typically low in these cases.
- *
- * It is possible for a Cell to become unused when threads that
- * once hashed to it terminate, as well as in the case where
- * doubling the table causes no thread to hash to it under
- * expanded mask. We do not try to detect or remove such cells,
- * under the assumption that for long-running instances, observed
- * contention levels will recur, so the cells will eventually be
- * needed again; and for short-lived ones, it does not matter.
- */
-
- private static final long serialVersionUID = -3403386352761423917L;
-
- /**
- * Padded variant of AtomicLong supporting only raw accesses plus CAS.
- * The value field is placed between pads, hoping that the JVM doesn't
- * reorder them.
- *
- * JVM intrinsics note: It would be possible to use a release-only
- * form of CAS here, if it were provided.
- */
- static final class Cell {
- volatile long p0, p1, p2, p3, p4, p5, p6;
- volatile long value;
- volatile long q0, q1, q2, q3, q4, q5, q6;
-
- Cell(long x) { value = x; }
-
- final boolean cas(long cmp, long val) {
- return UNSAFE.compareAndSwapLong(this, valueOffset, cmp, val);
- }
-
- // Unsafe mechanics
- private static final sun.misc.Unsafe UNSAFE;
- private static final long valueOffset;
-
- static {
- try {
- UNSAFE = getUnsafe();
- Class ak = Cell.class;
- valueOffset = UNSAFE.objectFieldOffset
- (ak.getDeclaredField("value"));
- } catch (Exception e) {
- throw new Error(e);
- }
- }
-
- }
-
- /**
- * Holder for the thread-local hash code. The code is initially
- * random, but may be set to a different value upon collisions.
- */
- static final class HashCode {
- static final Random rng = new Random();
- int code;
-
- HashCode() {
- int h = rng.nextInt(); // Avoid zero to allow xorShift rehash
- code = (h == 0) ? 1 : h;
- }
- }
-
- /**
- * The corresponding ThreadLocal class
- */
- static final class ThreadHashCode extends ThreadLocal