rainly

#对non-lock queue的简单分析#

今天看到 @梁斌penny 在打擂：http://coderpk.com

内容如下：

游戏规则：比赛由pennyliang，就是本人梁斌同志坐庄，我提交baseline代码（可执行程序），和部分代码，方便统一游戏规则。 10亿数据（每个数据看作一个同志），1个队列，10个线程push，10个线程pop,走完一遍，考察总耗时，耗时最短的获胜。我的代码在我自己机器10亿数据排队进出,耗时1分28秒，内存峰值256MB（CPU16核，真8核那种，Intel(R) Xeon(R) CPU E5540 @ 2.53GHz）

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

Make me a new CentOS linode

Notes:

Instructions written for CentOS 6.3
Change, me, myhost, myip etc. to your username, hostname, ip address and so on.
Run all commands as root unless otherwise directed.
You might want to look at mounting /var and /home on separate partitions.
I've just allowed all members of the wheel group to operate as root. This is the height of laziness and highlights the fact that I'm just a developer that's stolen a sysadmin's

	--
	-- Setup - Add plpgsql, create a parent table, create an initial child table,
	-- create the trigger and the initial trigger function.
	--

	-- We'll need plpgsql, so create it in your db if it's not already available.
	CREATE LANGUAGE plpgsql;

	-- Create a table to act as parent with the appropriate columns for your data.
	CREATE TABLE my_schema.my_data (name varchar(24), create_date timestamp);

	--
	-- DEPRECATED GIST
	-- ** Moved to a repo: https://github.com/imperialwicket/postgresql-time-series-table-partitions **
	--
	-- You should check the repository, this gist won't receive updates.
	--
	--
	--
	--
	--

	GRANT CONNECT ON DATABASE $dbName TO $user;
	GRANT USAGE ON SCHEMA $schema TO $user;
	GRANT SELECT ON ALL TABLES IN SCHEMA $schema TO $user;

	Default privileges
	ALTER DEFAULT PRIVILEGES IN SCHEMA $schema
	GRANT SELECT ON TABLES TO $user;

	see more at http://www.postgresql.org/docs/9.0/static/sql-alterdefaultprivileges.html

	# note: MySQL_maintenance.pl can be obtained from http://danbuettner.net/mysql-tools/

	# check, optimise and repair MySQL databases (extended check on Sunday, quick every other day)
	15 3 * * 0 root nice -n 19 /usr/local/sbin/MySQL_maintenance.pl --check-type=extended --optimize --repair --exclude-dbs=information_schema
	15 3 * * 1-6 root nice -n 19 /usr/local/sbin/MySQL_maintenance.pl --check-type=quick --optimize --repair --exclude-dbs=information_schema > /dev/null

	# dump all mysql databases once every 24 hours
	15 4 * * * root nice -n 19 mysqldump --opt --all-databases --allow-keywords \| gzip -9 > /var/local/backup/mysql/mysql_all.sql.gz

	# dump all databases once every 24 hours
	45 4 * * * root nice -n 19 su - postgres -c "pg_dumpall --clean" \| gzip -9 > /var/local/backup/postgres/postgres_all.sql.gz

	# vacuum all databases every night (full vacuum on Sunday night, lazy vacuum every other night)
	45 3 * * 0 root nice -n 19 su - postgres -c "vacuumdb --all --full --analyze"
	45 3 * * 1-6 root nice -n 19 su - postgres -c "vacuumdb --all --analyze --quiet"

	# re-index all databases once a week
	0 3 * * 0 root nice -n 19 su - postgres -c 'psql -t -c "select datname from pg_database order by datname;" \| xargs -n 1 -I"{}" -- psql -U postgres {} -c "reindex database {};"'

	/*
	12306 Auto Query => A javascript snippet to help you book tickets online.
	Copyright (C) 2011-2012 Jingqin Lynn

	Includes jQuery
	Copyright 2011, John Resig
	Dual licensed under the MIT or GPL Version 2 licenses.
	http://jquery.org/license

	Includes Sizzle.js

	source :rubygems

	gem "eventmachine", "0.12.10"
	gem "rack"