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laskfla / annotated_maps

Created March 27, 2016 12:46 — forked from rednaxelafx/annotated_maps

another memory layout example. JDK6u25 on AMD64 Ubuntu 10.10

	List of threads:

	4210 Thread-4
	4208 WatcherThread
	4209 Timer-0
	4207 Low Memory Detector
	4206 C2 CompilerThread1
	4205 C2 CompilerThread0
	4204 Signal Dispatcher
	4203 Finalizer

laskfla / latency.txt

Created April 23, 2017 12:56 — forked from jboner/latency.txt

Latency Numbers Every Programmer Should Know

	Latency Comparison Numbers
	--------------------------
	L1 cache reference 0.5 ns
	Branch mispredict 5 ns
	L2 cache reference 7 ns 14x L1 cache
	Mutex lock/unlock 25 ns
	Main memory reference 100 ns 20x L2 cache, 200x L1 cache
	Compress 1K bytes with Zippy 3,000 ns 3 us
	Send 1K bytes over 1 Gbps network 10,000 ns 10 us
	Read 4K randomly from SSD* 150,000 ns 150 us ~1GB/sec SSD

laskfla / DirectMemorySize.java

Created January 14, 2018 13:44 — forked from rednaxelafx/DirectMemorySize.java

An Serviceability-Agent based tool to see stats of NIO direct memory, as an alternative on JDK6 without JMX support for direct memory monitoring. Only works on JDK6; to work on JDK7 will need some tweaking because static variables are moved to Java mirror

	import java.io.*;
	import java.util.*;
	import sun.jvm.hotspot.memory.*;
	import sun.jvm.hotspot.oops.*;
	import sun.jvm.hotspot.debugger.*;
	import sun.jvm.hotspot.runtime.*;
	import sun.jvm.hotspot.tools.*;
	import sun.jvm.hotspot.utilities.*;

	public class DirectMemorySize extends Tool {

laskfla / MonBuffers.java

Created June 19, 2018 06:29 — forked from t3rmin4t0r/MonBuffers.java

Monitoring direct memory in the JVM (from https://blogs.oracle.com/alanb/entry/monitoring_direct_buffers, adapted for JDK8)

	import java.io.File;
	import java.util.*;
	import java.lang.management.BufferPoolMXBean;
	import java.lang.management.ManagementFactory;
	import javax.management.MBeanServerConnection;
	import javax.management.ObjectName;
	import javax.management.remote.*;

	import com.sun.tools.attach.VirtualMachine; // Attach API