Min Zhou coderplay

frequent YGC.

# To display the perf.data header info, please use --header/--header-only options.
#
#
# Total Lost Samples: 0
#
# Samples: 535K of event 'cycles'

TCP/IP传输层协议

此次花了三天时间读了 PART II-8 TCP/IP transport layer protocols 从第42章至第49章, 收获很大. 明白了以下一些问题:

为什么需要tcp? 同时又需要udp?
tcp/udp端口的意义
tcp 和 udp端口的区别, 是否可以在一个终端上同时使用相同的tcp端口和udp端口
tcp端口范围,为什么要保留一些端口
udp格式及为什么要这么设计udp格式
tcp的主要功能
MSS和MTU的区别及联系

  java.lang.Thread.State: TIMED_WAITING (parking)
   at sun.misc.Unsafe.park(Native Method)
   at java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:338)
   at org.apache.cassandra.utils.concurrent.WaitQueue$AbstractSignal.awaitUntil(WaitQueue.java:307)
   at org.apache.cassandra.utils.concurrent.SimpleCondition.await(SimpleCondition.java:63)
   at org.apache.cassandra.service.ReadCallback.await(ReadCallback.java:90)
   at org.apache.cassandra.service.ReadCallback.get(ReadCallback.java:100)
   at org.apache.cassandra.service.AbstractReadExecutor.get(AbstractReadExecutor.java:139)
   at org.apache.cassandra.service.StorageProxy.fetchRows(StorageProxy.java:1338)

	pool-1-thread-126" #152 prio=5 os_prio=0 tid=0x00007f34ec6ae800 nid=0xc03f waiting on condition [0x00007f3416be9000]
	java.lang.Thread.State: TIMED_WAITING (parking)
	at sun.misc.Unsafe.park(Native Method)
	- parking to wait for <0x0000000080451948> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject)
	at java.util.concurrent.locks.LockSupport.parkUntil(LockSupport.java:256)
	at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.awaitUntil(AbstractQueuedSynchronizer.java:2120)
	at org.apache.http.pool.AbstractConnPool.getPoolEntryBlocking(AbstractConnPool.java:378)
	at org.apache.http.pool.AbstractConnPool.access$200(AbstractConnPool.java:69)
	at org.apache.http.pool.AbstractConnPool$2.get(AbstractConnPool.java:246)
	- locked <0x00000005d0231ab8> (a org.apache.http.pool.AbstractConnPool$2)

	bash-3.2$ python
	Python 2.7.10 (default, Feb 6 2017, 23:53:20)
	[GCC 4.2.1 Compatible Apple LLVM 8.0.0 (clang-800.0.34)] on darwin
	Type "help", "copyright", "credits" or "license" for more information.
	>>> def func(arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8, arg9, arg10, arg11, arg12):
	def func(arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8, arg9, arg10, arg11, arg12):
	... return arg1+arg2+arg3+arg4+arg5+arg6+arg7+arg8+arg9+arg10+arg11+arg12
	return arg1+arg2+arg3+arg4+arg5+arg6+arg7+arg8+arg9+arg10+arg11+arg12
	...

	export PATH=/usr/local/sbin:$PATH

	export JAVA_HOME="$(/usr/libexec/java_home -v 1.8)"

	# GOLANG
	export GOPATH=$HOME/software/gopath
	export PATH=$PATH:$GOPATH/bin

	# GNU TAR
	export PATH=/usr/local/opt/gnu-tar/libexec/gnubin:$PATH

	#!/usr/bin/env bash

	set -e

	VER=$1
	PROJ="etcd"

	if [ -z "$1" ]; then
	echo "Usage: ${0} VERSION" >> /dev/stderr
	exit 255

	[defaults]
	timeout=20
	forks=20
	remote_user=ubuntu
	jinja2_extensions=jinja2.ext.do,jinja2.ext.i18n
	#

	[ssh_connection]
	# scp_if_ssh=True
	# pipelining=True

	66.69% java [kernel.kallsyms] [k] _raw_spin_unlock_irqrestore
	\|
	--- _raw_spin_unlock_irqrestore
	\|
	\|--99.96%-- compaction_alloc
	\| migrate_pages
	\| compact_zone
	\| try_to_compact_pages
	\| __alloc_pages_direct_compact
	\| __alloc_pages_nodemask

	/*
	* Licensed to the Apache Software Foundation (ASF) under one
	* or more contributor license agreements. See the NOTICE file
	* distributed with this work for additional information
	* regarding copyright ownership. The ASF licenses this file
	* to you under the Apache License, Version 2.0 (the
	* "License"); you may not use this file except in compliance
	* with the License. You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0