Chun Chen chenchun

Latency numbers every programmer should know

L1 cache reference ......................... 0.5 ns
Branch mispredict ............................ 5 ns
L2 cache reference ........................... 7 ns
Mutex lock/unlock ........................... 25 ns
Main memory reference ...................... 100 ns             
Compress 1K bytes with Zippy ............. 3,000 ns  =   3 µs
Send 2K bytes over 1 Gbps network ....... 20,000 ns  =  20 µs
SSD random read ........................ 150,000 ns  = 150 µs

Read 1 MB sequentially from memory ..... 250,000 ns = 250 µs

People

`:bowtie:`	😄 `:smile:`	😆 `:laughing:`
😊 `:blush:`	😃 `:smiley:`	☺️ `:relaxed:`
😏 `:smirk:`	😍 `:heart_eyes:`	😘 `:kissing_heart:`
😚 `:kissing_closed_eyes:`	😳 `:flushed:`	😌 `:relieved:`
😆 `:satisfied:`	😁 `:grin:`	😉 `:wink:`
😜 `:stuck_out_tongue_winking_eye:`	😝 `:stuck_out_tongue_closed_eyes:`	😀 `:grinning:`
😗 `:kissing:`	😙 `:kissing_smiling_eyes:`	😛 `:stuck_out_tongue:`

	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.*;

	public class DumpClassURL extends Tool {
	public void run() {

	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 {

	#!/bin/bash

	# Get IP for specified host using 'http://ping.eu/ping', then write it to hosts.

	if [ $# -ne 1 ]; then
	echo "Usage: $0 host"
	echo " e.g. # $0 baidu.com"
	exit 0
	fi

	func ip2int(ip net.IP) uint32 {
	if len(ip) == 16 {
	return binary.BigEndian.Uint32(ip[12:16])
	}
	return binary.BigEndian.Uint32(ip)
	}

	func int2ip(nn uint32) net.IP {
	ip := make(net.IP, 4)
	binary.BigEndian.PutUint32(ip, nn)

	#!/bin/bash

	set -e
	set -u
	#set -x

	SSH_KEY="05:8b:8f:f5:09:35:ae:61:a9:3b:21:ea:1c:36:bf:0c"
	USER_DATA_FILE="$(dirname $0)/vps.userdata"

	### sub functions

	// Use Gists to store code you would like to remember later on
	console.log(window); // log the "window" object to the console