frogspawn

中文版本

Concept:

Like frogs spawning, densely producing large quantities of eggs for future use

Objective:

Serves as an in-memory object pool with pre-allocation and pre-processing

Use Cases

Used in low-latency scenarios to replace allocation of numerous stateless small objects. Prevents latency fluctuations caused by GC.

Example: During interface serialization/deserialization

SerializeCompareSample

Usage

Managed objects need to implement a specific interface Resettable

public class DemoPojo implements Resettable {
    ...
}

Need to implement a creator

public class DemoPojoCreator implements ObjectCreator<DemoPojo> {
    @Override
    public DemoPojo create() {
        return new DemoPojo();
    }
}

Build object pool

PoolStrategy strategy = new PoolStrategy(
        FetchStrategy.MUST_FETCH_IN_POOL, FetchFailStrategy.CALL_CREATOR, true);
ObjectsMemoryPool<DemoPojo> pool =
        ObjectsMemoryPoolFactory.newPool(new DemoPojoCreator(), SIZE, strategy);

Usage

try{
    DemoPojo pojo = pojoPool.fetch();
    // TODO using pojo
    ...
}finally{
    pojoPool.release(pojo);
}

Three Available Modes

Currently supports three different modes:

1. Must fetch from pool

   PoolStrategy strategy = new PoolStrategy(
       FetchStrategy.MUST_FETCH_IN_POOL, FetchFailStrategy.CALL_CREATOR, true);
   ObjectsMemoryPool<DemoPojo> pool =
       ObjectsMemoryPoolFactory.newPool(new DemoPojoCreator(), SIZE, strategy);

2. Return null after certain fetch attempts

   PoolStrategy strategy = new PoolStrategy(
       FetchStrategy.FETCH_FAIL_AS_NULL, FetchFailStrategy.CALL_CREATOR, true);
   ObjectsMemoryPool<DemoPojo> pojoPool =
       ObjectsMemoryPoolFactory.newPool(new DemoPojoCreator(), SIZE, strategy);

3. Create new object after certain fetch attempts

   PoolStrategy strategy = new PoolStrategy(
       FetchStrategy.FETCH_FAIL_AS_NEW, FetchFailStrategy.CALL_CREATOR, true);
   ObjectsMemoryPool<DemoPojo> pojoPool =
       ObjectsMemoryPoolFactory.newPool(new DemoPojoCreator(), SIZE, strategy);

The last option is the default.

Optional Parameters

• -Dfrogspawn.fetch.times: Maximum fetch attempts, default: 100
• -Dfrogspawn.max.capacity: Maximum pool capacity, default: 67108864 (65536*1024)
• -Dfrogspawn.cache.capacity: Thread cache capacity, default: 8, maximum: 64. Setting to 1 provides maximum performance.

False Sharing Considerations

The following content requires running on JDK8 specifically - no higher, no lower!!

@sun.misc.Contended Source Code The annotation mentions it may be ineffective for subclasses. Therefore, current usage in the code might be ineffective.

Additional documentation states that the @Contended annotation requires JVM parameter -XX:-RestrictContended to be enabled.

Changelog

ChangeLog