chenk008

import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class RegexMatcheUtils {

	public static void main(String[] args) {

		String result = replaceWithHandler("${x}*get(@36,3)", "@\\w+",
				new RegexMatcheHandler() {

chenk008

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 {

chenk008

import java.lang.instrument.Instrumentation;
import java.net.URL;
import java.security.CodeSource;
import java.security.ProtectionDomain;
import java.util.Arrays;
import java.util.Comparator;

public class DumpClassURL {
  public static void agentmain(String agentArgs, Instrumentation inst) {
    Class<?>[] classes = inst.getAllLoadedClasses();

chenk008

在java机器上执行：
tcpdump -i eth1 -s 0 -l -w - dst  port 3306 | strings


-s 0 : 抓取数据包时默认抓取长度为68字节。加上-s 0 后可以抓到完整的数据包
-l:表示每行都输出到文件，不缓存
-w - :输出到console
dst  port 3306 :目标端口，必须写在最后

chenk008

Enable native memory tracking in JVM by specifying the following flag

-XX:NativeMemoryTracking=detail

Known the <PID> of the java process

jps

To print ps based RSS

ps -p <PID> -o pcpu,rss,size,vsize

To print native memory tracking summary

chenk008

指标参考下面几个内容整理。

• basic-perfomance
• tsar https://github.com/alibaba/tsar/blob/master/info.md#io
• netflixs http://techblog.netflix.com/2015/04/introducing-vector-netflixs-on-host.html
• openfalcon http://book.open-falcon.com/zh/faq/linux-metrics.html

含义参考了: 对应的 manpage, kernel doc。

系统监控

chenk008

Common Options

-#, --progress-bar Make curl display a simple progress bar instead of the more informational standard meter.

-b, --cookie <name=data> Supply cookie with request. If no =, then specifies the cookie file to use (see -c).

-c, --cookie-jar <file name> File to save response cookies to.

chenk008

Overly aggressive CFS

We're looking at CPU bandwidth control via CFS:

• https://www.kernel.org/doc/Documentation/scheduler/sched-bwc.txt

Reproduction program

Program does number of iterations, in each iteration we burn CPU in small chunks until we get 5ms of real time spent. On each iteration we also print how much

chenk008

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <netinet/in.h>

#define SERVER_ADDR "173.194.72.94"
#define SERVER_PORT 80

int main()

chenk008

xstat() {
  for target in "${@}"; do
    inode=$(ls -di "${target}" | cut -d ' ' -f 1)
    fs=$(df "${target}"  | tail -1 | awk '{print $1}')
    crtime=$(sudo debugfs -R 'stat <'"${inode}"'>' "${fs}" 2>/dev/null | 
    grep -oP 'crtime.*--\s*\K.*')
    printf "%s\t%s\n" "${crtime}" "${target}"
  done
}