Class CPUSampler

java.lang.Object

tools.CPUSampler

public class CPUSampler
extends Object

以取樣方式剖析伺服器執行緒 CPU 熱點的效能診斷工具。

本類別以單例模式運作，啟動背景執行緒 SamplerThread， 每隔 interval 毫秒（預設 5 ms）呼叫 Thread.getAllStackTraces() 收集全執行緒堆疊快照，統計出現頻率最高的呼叫路徑。

主要操作流程：

• 以 addIncluded(prefix) 限縮要納入統計的套件前綴。
• 呼叫 start() 開始取樣，stop() 停止。
• 以 getTopConsumers() 取得 SampledStacktraces 結果， 或以 save(Writer, minInvocations, topMethods) 輸出報告。
• reset() 清除所有已累積的樣本。

取樣結果以 StacktraceWithCount 物件（含命中次數與堆疊）排序後回傳， 方便定位 GC 壓力、鎖競爭或 I/O 阻塞等熱點。

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	CPUSampler.SampledStacktraces
static class	CPUSampler.StacktraceWithCount

Constructor Summary

Constructors

Constructor	Description
CPUSampler()

Method Summary

Modifier and Type	Method	Description
void	addIncluded(String include)
static CPUSampler	getInstance()
CPUSampler.SampledStacktraces	getTopConsumers()
void	reset()
void	save(Writer writer, int minInvocations, int topMethods)
void	setInterval(long millis)
void	start()
void	stop()

Methods inherited from class Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

CPUSampler

public CPUSampler()

Method Details

getInstance

public static CPUSampler getInstance()

setInterval

public void setInterval(long millis)

addIncluded

public void addIncluded(String include)

reset

public void reset()

start

public void start()

stop

public void stop()

getTopConsumers

public CPUSampler.SampledStacktraces getTopConsumers()

save

public void save(Writer writer,
 int minInvocations,
 int topMethods)
          throws IOException

Throws:

IOException