承德双桥：长效管理筑根基 城乡共美焕新颜

在联络型数据库中，承德长效实体以及实体间的联络均由单一的结构类型来表明，这种逻辑结构是一张二维表。

一、双桥准备作业NXP源码途径：双桥ELF1开发板材料包\07-NXP原厂材料\07-1NXP官方源码\linux-imx-imx_4.1.15_2.0.0_ga.tar.bz21、将NXP源码拷贝到开发环境home/root/work目录下解压elfubuntu:~/work$tarjvxflinux-imx-imx_4.1.15_2.0.0_ga.tar.bz2elfubuntu:~/work$cdlinux-imx-imx_4.1.15_2.0.0_ga/elfubuntu:~/work/linux-imx-imx_4.1.15_2.0.0_ga$ls2、增加默许装备文件将arch/arm/configs途径下的imx_v7_mfg_defconfig仿制一份，命名为imx6ull_elf1_defconfigelfubuntu:~/work/linux-imx-imx_4.1.15_2.0.0_ga$cparch/arm/configs/imx_v7_mfg_defconfigarch/arm/configs/imx6ull_elf1_defconfig3、增加ELF1设备树将arch/arm/boot/dts途径下的imx6ull-14x14-evk.dts仿制一份，命名为imx6ull-elf1-emmc.dtselfubuntu:~/work/linux-imx-imx_4.1.15_2.0.0_ga$cparch/arm/boot/dts/imx6ull-14x14-evk.dtsarch/arm/boot/dts/imx6ull-elf1-emmc.dts翻开arch/arm/boot/dts/Makefile，找到CONFIG_SOC_IMX6ULL，将imx6ull-elf1-emmc.dts增加到Makefile中elfubuntu:~/work/linux-imx-imx_4.1.15_2.0.0_ga$viarch/arm/boot/dts/Makefile4、树立穿插编译脚本树立一个编译脚本build.shelfubuntu:~/work/linux-imx-imx_4.1.15_2.0.0_ga$vimbuild.sh增加以下内容，保存退出#!/bin/bashexportCPUS=`grep-cprocessor/proc/cpuinfo`source/opt/fsl-imx-x11/4.1.15-2.0.0/environment-setup-cortexa7hf-neon-poky-linux-gnueabimakedistcleanmakeimx6ull_elf1_defconfigmake-j${CPUS}rm-rf./.tmpmakemodules_installINSTALL_MOD_PATH=./.tmp/rootfs/cd.tmp/rootfs/tar-jcvfmodules.tar.bz2*给予脚本权限elfubuntu:~/work/linux-imx-imx_4.1.15_2.0.0_ga$chmod777build.sh二、适配UART1、硬件原理（1）UART1从原理图中能够得到咱们运用的UART1_RXD和UART1_TXD引脚对应的连接器引脚编号别离为27和28。测验RS232(UART7)运用指令：管理rootELF1:~#elf1_cmd_serialportttymxc6-o-b9600-taabbccddeeff1至此，管理就完成了在NXP源码基础上适配ELF1开发板的UART功用，希望这份详实的攻略能为正在阅览的小伙伴带来实质性的助益与启示。

针对ELF1开发板，筑根实践引出了4路UART接口供开发者运用，详细包含UART1、UART2、UART3以及UART7。上一节中现已确认了咱们运用的UART1和UART2对应的引脚PADNAME，基城UART1：基城UART1_RX_DATA和UART1_TX_DATA，UART2：UART2_RX_DATA和UART2_TX_DATA，比照arch/arm/boot/dts/imx6ull-elf1-emmc.dts文件中已装备好的IOMUX信息，能够看到是共同的：由上图可知，UART2的IOMUX节点uart2grp下装备了流控引脚RTS和CTS，咱们板子没有引出流控引脚，所以这儿注释掉流控装备：（2）UART3由上一节确认了咱们运用的UART3收发引脚PADNAME别离为UART3_RX_DATA和UART3_TX_DATA。UART2也现已装备好，乡共新颜咱们只需将其间的流控功用去掉就能够了：乡共新颜&uart2{pinctrl-names=default;pinctrl-0=;/*fsl,uart-has-rtscts;*//*forDTEmode,addbelowchange*//*fsl,dte-mode;*//*pinctrl-0=;*/status=okay;}按照上述办法，顺次增加UART3和UART7节点相关特点：&uart3{pinctrl-names=default;pinctrl-0=;status=okay;};&uart7{pinctrl-names=default;pinctrl-0=;status=okay;};增加后效果如下：4、编译独自编译设备树：./opt/fsl-imx-x11/4.1.15-2.0.0/environment-setup-cortexa7hf-neon-poky-linux-gnueabielfubuntu:~/work/linux-imx-imx_4.1.15_2.0.0_ga$makedtbs运用scp将设备树拷贝到开发板：elfubuntu:~/work/linux-imx-imx_4.1.15_2.0.0_ga$scparch/arm/boot/dts/imx6ull-elf\1-emmc.dtbroot172.16.0.175:/run/media/mmcblk1p1/进行sync操作后重启开发板：发动之后，能够看到在/dev目录下生成节点ttymxc0、ttymxc1、ttymxc2、ttymxc6，别离对应咱们增加的UART1，UART2，UART3，UART7

privatestaticbooleanpassLocalCheck(FlowRulerule,Contextcontext,DefaultNodenode,intacquireCount,booleanprioritized){//依据战略挑选Node来进行核算（能够是自身Node、美焕相关的Node、美焕指定的链路）NodeselectedNode=selectNodeByRequesterAndStrategy(rule,context,node);if(selectedNode==null){returntrue;}returnrule.getRater().canPass(selectedNode,acquireCount,prioritized);}staticNodeselectNodeByRequesterAndStrategy(/*NonNull*/FlowRulerule,Contextcontext,DefaultNodenode){//limitApp是拜访操控运用的，默许是default，不约束来历StringlimitApp=rule.getLimitApp();//拿到限流战略intstrategy=rule.getStrategy();Stringorigin=context.getOrigin();//依据调用来历做鉴权if(limitApp.equals(origin)&&filterOrigin(origin)){if(strategy==RuleConstant.STRATEGY_DIRECT){//Matcheslimitorigin,returnoriginstatisticnode.returncontext.getOriginNode();}//returnselectReferenceNode(rule,context,node);}elseif(RuleConstant.LIMIT_APP_DEFAULT.equals(limitApp)){if(strategy==RuleConstant.STRATEGY_DIRECT){//Returntheclusternode.returnnode.getClusterNode();}returnselectReferenceNode(rule,context,node);}elseif(RuleConstant.LIMIT_APP_OTHER.equals(limitApp)&&FlowRuleManager.isOtherOrigin(origin,rule.getResource())){if(strategy==RuleConstant.STRATEGY_DIRECT){returncontext.getOriginNode();}returnselectReferenceNode(rule,context,node);}returnnull;}staticNodeselectReferenceNode(FlowRulerule,Contextcontext,DefaultNodenode){StringrefResource=rule.getRefResource();intstrategy=rule.getStrategy();if(StringUtil.isEmpty(refResource)){returnnull;}if(strategy==RuleConstant.STRATEGY_RELATE){returnClusterBuilderSlot.getClusterNode(refResource);}if(strategy==RuleConstant.STRATEGY_CHAIN){if(!refResource.equals(context.getName())){returnnull;}returnnode;}//Nonode.returnnull;}//此代码是load限流规矩时依据规矩初始化流量整形操控器的逻辑，rule.getRater()回来TrafficShapingControllerprivatestaticTrafficShapingControllergenerateRater(/*Valid*/FlowRulerule){if(rule.getGrade()==RuleConstant.FLOW_GRADE_QPS){switch(rule.getControlBehavior()){//预热形式回来WarmUpControllercaseRuleConstant.CONTROL_BEHAVIOR_WARM_UP:returnnewWarmUpController(rule.getCount(),rule.getWarmUpPeriodSec(),ColdFactorProperty.coldFactor);//排队形式回来ThrottlingControllercaseRuleConstant.CONTROL_BEHAVIOR_RATE_LIMITER:returnnewThrottlingController(rule.getMaxQueueingTimeMs(),rule.getCount());//预热+排队形式回来WarmUpRateLimiterControllercaseRuleConstant.CONTROL_BEHAVIOR_WARM_UP_RATE_LIMITER:returnnewWarmUpRateLimiterController(rule.getCount(),rule.getWarmUpPeriodSec(),rule.getMaxQueueingTimeMs(),ColdFactorProperty.coldFactor);caseRuleConstant.CONTROL_BEHAVIOR_DEFAULT:default://Defaultmodeorunknownmode:defaulttrafficshapingcontroller(fast-reject).}}//默许是DefaultControllerreturnnewDefaultController(rule.getCount(),rule.getGrade());}Sentinel单机限流算法上面咱们看到依据限流规矩controlBehavior特点（流控作用），会初始化以下完结：•DefaultController：是一个十分典型的滑动窗口计数器算法完结，将当时核算的qps和恳求进来的qps进行求和，小于限流值则经过，大于则核算一个等候时刻，稍后再试•ThrottlingController：是漏斗算法的完结，完结思路现已在源码片段中加了补白•WarmUpController：完结参阅了Guava的带预热的RateLimiter，区别是Guava侧重于恳求距离，相似前面说到的令牌桶，而Sentinel更重视于恳求数，和令牌桶算法有点相似•WarmUpRateLimiterController：低水位运用预热算法，高水位运用滑动窗口计数器算法排队。•当后续的slot经过，承德长效没有抛出BlockException反常，阐明该资源被成功调用，则添加履行线程数和经过的恳求数等信息。

您能够在操控台中看到接入运用的单台机器秒级数据，双桥乃至500台以下规划的集群的汇总运转状况。

//以分钟级的核算特点为例，管理看一下时刻窗口初始化进程privatetransientMetricrollingCounterInMinute=newArrayMetric(60,60*1000,false);publicLeapArray(intsampleCount,intintervalInMs){AssertUtil.isTrue(sampleCount>0,bucketcountisinvalid:+sampleCount);AssertUtil.isTrue(intervalInMs>0,totaltimeintervaloftheslidingwindowshouldbepositive);AssertUtil.isTrue(intervalInMs%sampleCount==0,timespanneedstobeevenlydivided);//windowLengthInMs=60*1000/60=1000滑动窗口时刻长度，管理可见sentinel默许将单位时刻分为了60个滑动窗口进行数据核算this.windowLengthInMs=intervalInMs/sampleCount;//60*1000this.intervalInMs=intervalInMs;//60this.intervalInSecond=intervalInMs/1000.0;//60this.sampleCount=sampleCount;//数组长度60this.array=newAtomicReferenceArray(sampleCount);}/***Getbucketitematprovidedtimestamp.**paramtimeMillisavalidtimestampinmilliseconds*returncurrentbucketitematprovidedtimestampifthetimeisvalid;nulliftimeisinvalid*/publicWindowWrapcurrentWindow(longtimeMillis){if(timeMillisold.windowStart()){/**(old)*B0B1B2NULLB4*|_______||_______|_______|_______|_______|_______||___*...120014001600180020002200timestamp*^*time=1676*startTimeofBucket2:400,deprecated,shouldbereset**Ifthestarttimestampofoldbucketisbehindprovidedtime,thatmeans*thebucketisdeprecated.Wehavetoresetthebuckettocurrent{codewindowStart}.*Notethattheresetandclean-upoperationsarehardtobeatomic,*soweneedaupdatelocktoguaranteethecorrectnessofbucketupdate.**Theupdatelockisconditional(tinyscope)andwilltakeeffectonlywhen*bucketisdeprecated,soinmostcasesitwontleadtoperformanceloss.*/if(updateLock.tryLock()){try{//Successfullygettheupdatelock,nowweresetthebucket.returnresetWindowTo(old,windowStart);}finally{updateLock.unlock();}}else{//Contentionfailed,thethreadwillyielditstimeslicetowaitforbucketavailable.Thread.yield();}}elseif(windowStart。3.更好的数据可视化：筑根图数据库能够将数据可视化为图形，运用户更简略了解和剖析数据。

•更好的数据剖析支撑：基城因为列式数据库能够处理大规划的数据，它能够支撑更凌乱的数据剖析和处理操作，例如数据发掘、机器学习等。经过上图能够发现，乡共新颜时刻轮算法不再使命行列作为数据结构，轮询线程不再担任遍历一切使命，而是只是遍历时刻刻度。

日常开发进程中运用的Dubbo、美焕Netty、Akka、Quartz、ZooKeeper、Kafka等各种中间件，也都有环形行列的思维。4.3.1共同性Hash环先来看一下，承德长效典型Hash算法结构如下：承德长效以上图Hash策略为例，当节点数N发生改变的时分之前一切的hash映射简直悉数失效，假如集群是无状况的服务，却是没什么作业，可是假如是散布式缓存这种场景，就会导致比较严重的问题。

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