Java Memory Model

JVM内存模型 Java内存模型 Java内存模型是共享内存的并发模型,线程之间主要通过读-写共享变量(堆内存中的实例域,静态域和数组元素)来完成隐式通信。 Java 内存模型(JMM)控制 Java 线程之间的通信,决定一个线程对共享变量的写入何时对另一个线程可见。 计算机高速缓存和缓存一致性 计算机在高速的 CPU 和相对低速的存储设备之间使用高速缓存,作为内存和处理器之间的缓... 阅读详情

http://tutorials.jenkov.com/java-concurrency/java-memory-model.html


一个好地方解释的比较清楚Java内存模型以及对应硬件(寄存器,CPU缓存,主内存)之间的关联


The division of thread stack and heap among CPU internal registers, CPU cache and main memory.


Race Condition Issues in the Java Memory Model.

文件上传漏洞攻击与防范方法 文件上传漏洞攻击与防范方法 文件上传漏洞简介: 文件上传漏洞是web安全中经常用到的一种漏洞形式。是对数据与代码分离原则的一种攻击。上传漏洞顾名思义,就是攻击者上传了一个可执行文件如木马,病毒,恶意脚本,WebShell等到服务器执行,并最终获得网站控制权限的高危漏洞。 文件上传漏洞危害: 上传漏洞与SQL注入或 XSS相比 , 其风险更大 , 如果 Web应用程序存在上传漏洞 , 攻击者上传... 阅读详情

相关推荐

ADS RFpro 射频阻抗仿真步骤

导入器件后,在库里面选取器件的对应模型,如图所示我们选取10pf 系统自带的村田模型。选取网络上的器件,拖入到下面component Models。导入成功后,截取需要仿真的区域(不截取仿真时间会非常长),可以生成对应如下原理图,通过原理图继续调整仿真。图上找到需要仿真链路上的网络,右键设置为信号。的叠层信息,按照PCB板厂提供信息填写完整。选择仿真的频率范围和频点数,生成如下图的RFPro仿真界。,然后再把GND也添加到下面。按图设置截取需要仿真的部分。添加成功后 网络就有了,15 双击run开始仿真。

m0_72954480的博客 3215

并发编程(三) - 重排序,happens-before原则,顺序一致性

重排序是指编译器和处理器为了优化程序性能而对指令序列进行重新排序的一种手段。 上一篇文章中已经介绍了从Java源代码到最终实际执行的指令序列,会分别经历下面3种重排序: 1属于编译器重排序,2和3属于处理器重排序。 这些重排序可能会导致多线程程序出现内存可见性问题。在单线程程序中,对存在控制依赖的操作重排序,不会改变执行结果(这也是as-if-serial语义允许对存在控制依赖的操作做重排序的原因);但在多线程程序中,对存在控制依赖的操作重排序,可能会改变程序的执行结果。 1.数据依...

ForestCat的专栏 1278

从理论到实践:笛卡尔空间阻抗控制的实现挑战与变体解析

本文深入探讨了笛卡尔空间阻抗控制的核心原理、工程实现中的五大挑战及经典变体实战解析。通过详细的数学建模和实际案例分析,揭示了阻抗控制在工业机器人、医疗设备等领域的应用价值,特别是在力感知精度、动力学模型校准和实时计算等方面的关键技术突破。

weixin_30952535的博客 448

Java内存模型(Memory Model)

    Java内存模型,Java Memory Model,我个人更喜欢“Java存储模型”的译法。  介绍  如前所述,JVM被设计成一台抽象的虚拟计算机,JVM的并发问题及解决方案与物理计算机中的并发问题有很多相似之处。  由于现代计算机的内存与CPU在运算速度上的巨大差别,通常会加入一层更接近CPU读写速度的高速缓存(Cache),将运算使用到的数据复制到Cache中,让运算能加速进行,运...

weixin_34015566的博客 268

Win10右键新建菜单丢了记事本?别慌!5分钟教你用注册表找回来(附权限设置避坑指南)

本文详细指导如何通过注册表编辑器恢复Win10右键新建菜单中丢失的记事本选项,包括重建键值结构、配置ShellNew项及设置权限等关键步骤。特别提供权限避坑指南,确保修改持久有效,帮助用户快速解决这一常见但困扰的问题。

weixin_31714129的博客 854

检索生成(RAG) vs 长文本大模型:实际应用中如何选择?

大模型的上下文理解能力直接影响到 LLMs 在复杂任务和长对话中的表现。本期内容聚焦于两种主流技术:长上下文(Large Context Windows)和检索增强生成(RAG)。这两种技术各有何优势?在实际应用中,我们又该如何权衡选择?文章不仅详细阐述了这两种技术的工作原理,还深入分析了它们在效率、准确性和实施成本等方面的差异。文章特别提到了在执行重复性任务时使用 Context Caching 优化长上下文的优势,然而,缓存策略的效果很大程度上取决于提示词的可预测性。

2401_85782938的博客 1254

Java内存模型(JMM)

一. JMM的定义 JMM(Java内存模型 Java Memory Model,简称JMM)本身是一种抽象的概念并不真实存在它仅仅描述的是一组约定或规范,通过这组规范定义了程序中(尤其是多线程)各个变量的读写访问方式并决定一个线程对共享变量的写入以及如何变成对另一个线程可见,关键技术点都是围绕多线程的原子性、可见性和有序性展开的原则: JMM的关键技术点都是围绕多线程的原子性、可见性和有序性展开的作用:1 通过JMM来实现线程和主内存之间的抽象关系。...

枫陵的博客 537

Fortran基础编程(3)——格式化输出

本篇推文将进一步讲解Fortran基础语法中格式化输出与声明部分,让我们的代码更加美观起来吧~

qq_45715554的博客 3826

Java内存模型(Memory Model)

java内存模型、指令重排、JMM、happens-before

qq_73181349的博客 1509

【线粒体基因组数据提交实战】从注释校验到GenBank批量入库的避坑指南

本文详细介绍了线粒体基因组数据从注释校验到GenBank批量上传的全流程避坑指南。重点解析了GB2sequin工具的正确使用方法、TBL注释文件的精修技巧,以及BankIt平台提交的隐藏要点,帮助科研人员高效完成NCBI数据提交,特别适合需要批量上传线粒体基因组数据的研究者。

weixin_28726671的博客 440

【系统架构设计师】二十六、论文写作要点

论文写作概述:时间所需120分钟;题目可四选一,必有一题考察软件架构,总有一款适合你;考察形式是机试(开心,再也不用担心字丑了),约2500字。

帅次的博客 4597

java memory model

java memory model jsr 133 FAQ

gonaYet的博客 257

廖雪峰Python教程[完整版]

廖雪峰的python教程整理的,已经排好版了,而且还是完整的,适合小白

JMM(Java Memory Model)

JMM(Java Memory Model的缩写)简介:

yang13676084606的博客 149

老版QQ原生表情gif动态

这是老版的QQ表情,不过全是动态的的,Windows照片查看器是不会动的,可以右击用浏览器打开查看,再说一遍是老版的,只是分享给宁愿用老版也要动态的人。

霍尼韦尔SoftMaster使用说明

霍尼韦尔SoftMaster使用说明

Java memory model(JMM)的理解

总结:JMM 是一种规范,目的是解决由于多线程通过共享内存进行通信时,存在的本地内存数据不一致、编译器会对代码指令重排序、处理器会对代码乱序执行等带来的问题。目的是保证并发编程场景中的原子性、可见性、有序性。 总结的很精辟! 感谢Hollis总结...

Otar 283

深度学习工具包 DeepLearningToolbox

深度学习工具包Deprecation notice.-----This toolbox is outdated and no longer maintained.There are much better tools available for deep learning than this toolbox, e.g. [Theano](http://deeplearning.net/software/theano/), [torch](http://torch.ch/) or [tensorflow](http://www.tensorflow.org/)I would suggest you use one of the tools mentioned above rather than use this toolbox.Best, Rasmus.DeepLearnToolbox================A Matlab toolbox for Deep Learning.Deep Learning is a new subfield of machine learning that focuses on learning deep hierarchical models of data.It is inspired by the human brain's apparent deep (layered, hierarchical) architecture.A good overview of the theory of Deep Learning theory is[Learning Deep Architectures for AI](http://www.iro.umontreal.ca/~bengioy/papers/ftml_book.pdf)For a more informal introduction, see the following videos by Geoffrey Hinton and Andrew Ng.* [The Next Generation of Neural Networks](http://www.youtube.com/watch?v=AyzOUbkUf3M) (Hinton, 2007)* [Recent Developments in Deep Learning](http://www.youtube.com/watch?v=VdIURAu1-aU) (Hinton, 2010)* [Unsupervised Feature Learning and Deep Learning](http://www.youtube.com/watch?v=ZmNOAtZIgIk) (Ng, 2011)If you use this toolbox in your research please cite [Prediction as a candidate for learning deep hierarchical models of data](http://www2.imm.dtu.dk/pubdb/views/publication_details.php?id=6284)```@MASTERSTHESIS\{IMM2012-06284, author = "R. B. Palm", title = "Prediction as a candidate for learning deep hierarchical models of data", year = "2012",}```Contact: rasmusbergpalm at gmail dot comDirectories included in the toolbox-----------------------------------`NN/` - A library for Feedforward Backpropagation Neural Networks`CNN/` - A library for Convolutional Neural Networks`DBN/` - A library for Deep Belief Networks`SAE/` - A library for Stacked Auto-Encoders`CAE/` - A library for Convolutional Auto-Encoders`util/` - Utility functions used by the libraries`data/` - Data used by the examples`tests/` - unit tests to verify toolbox is workingFor references on each library check REFS.mdSetup-----1. Download.2. addpath(genpath('DeepLearnToolbox'));Example: Deep Belief Network---------------------```matlabfunction test_example_DBNload mnist_uint8;train_x = double(train_x) / 255;test_x = double(test_x) / 255;train_y = double(train_y);test_y = double(test_y);%% ex1 train a 100 hidden unit RBM and visualize its weightsrand('state',0)dbn.sizes = [100];opts.numepochs = 1;opts.batchsize = 100;opts.momentum = 0;opts.alpha = 1;dbn = dbnsetup(dbn, train_x, opts);dbn = dbntrain(dbn, train_x, opts);figure; visualize(dbn.rbm{1}.W'); % Visualize the RBM weights%% ex2 train a 100-100 hidden unit DBN and use its weights to initialize a NNrand('state',0)%train dbndbn.sizes = [100 100];opts.numepochs = 1;opts.batchsize = 100;opts.momentum = 0;opts.alpha = 1;dbn = dbnsetup(dbn, train_x, opts);dbn = dbntrain(dbn, train_x, opts);%unfold dbn to nnnn = dbnunfoldtonn(dbn, 10);nn.activation_function = 'sigm';%train nnopts.numepochs = 1;opts.batchsize = 100;nn = nntrain(nn, train_x, train_y, opts);[er, bad] = nntest(nn, test_x, test_y);assert(er < 0.10, 'Too big error');```Example: Stacked Auto-Encoders---------------------```matlabfunction test_example_SAEload mnist_uint8;train_x = double(train_x)/255;test_x = double(test_x)/255;train_y = double(train_y);test_y = double(test_y);%% ex1 train a 100 hidden unit SDAE and use it to initialize a FFNN% Setup and train a stacked denoising autoencoder (SDAE)rand('state',0)sae = saesetup([784 100]);sae.ae{1}.activation_function = 'sigm';sae.ae{1}.learningRate = 1;sae.ae{1}.inputZeroMaskedFraction = 0.5;opts.numepochs = 1;opts.batchsize = 100;sae = saetrain(sae, train_x, opts);visualize(sae.ae{1}.W{1}(:,2:end)')% Use the SDAE to initialize a FFNNnn = nnsetup([784 100 10]);nn.activation_function = 'sigm';nn.learningRate = 1;nn.W{1} = sae.ae{1}.W{1};% Train the FFNNopts.numepochs = 1;opts.batchsize = 100;nn = nntrain(nn, train_x, train_y, opts);[er, bad] = nntest(nn, test_x, test_y);assert(er < 0.16, 'Too big error');```Example: Convolutional Neural Nets---------------------```matlabfunction test_example_CNNload mnist_uint8;train_x = double(reshape(train_x',28,28,60000))/255;test_x = double(reshape(test_x',28,28,10000))/255;train_y = double(train_y');test_y = double(test_y');%% ex1 Train a 6c-2s-12c-2s Convolutional neural network %will run 1 epoch in about 200 second and get around 11% error. %With 100 epochs you'll get around 1.2% errorrand('state',0)cnn.layers = { struct('type', 'i') %input layer struct('type', 'c', 'outputmaps', 6, 'kernelsize', 5) %convolution layer struct('type', 's', 'scale', 2) %sub sampling layer struct('type', 'c', 'outputmaps', 12, 'kernelsize', 5) %convolution layer struct('type', 's', 'scale', 2) %subsampling layer};cnn = cnnsetup(cnn, train_x, train_y);opts.alpha = 1;opts.batchsize = 50;opts.numepochs = 1;cnn = cnntrain(cnn, train_x, train_y, opts);[er, bad] = cnntest(cnn, test_x, test_y);%plot mean squared errorfigure; plot(cnn.rL);assert(er<0.12, 'Too big error');```Example: Neural Networks---------------------```matlabfunction test_example_NNload mnist_uint8;train_x = double(train_x) / 255;test_x = double(test_x) / 255;train_y = double(train_y);test_y = double(test_y);% normalize[train_x, mu, sigma] = zscore(train_x);test_x = normalize(test_x, mu, sigma);%% ex1 vanilla neural netrand('state',0)nn = nnsetup([784 100 10]);opts.numepochs = 1; % Number of full sweeps through dataopts.batchsize = 100; % Take a mean gradient step over this many samples[nn, L] = nntrain(nn, train_x, train_y, opts);[er, bad] = nntest(nn, test_x, test_y);assert(er < 0.08, 'Too big error');%% ex2 neural net with L2 weight decayrand('state',0)nn = nnsetup([784 100 10]);nn.weightPenaltyL2 = 1e-4; % L2 weight decayopts.numepochs = 1; % Number of full sweeps through dataopts.batchsize = 100; % Take a mean gradient step over this many samplesnn = nntrain(nn, train_x, train_y, opts);[er, bad] = nntest(nn, test_x, test_y);assert(er < 0.1, 'Too big error');%% ex3 neural net with dropoutrand('state',0)nn = nnsetup([784 100 10]);nn.dropoutFraction = 0.5; % Dropout fraction opts.numepochs = 1; % Number of full sweeps through dataopts.batchsize = 100; % Take a mean gradient step over this many samplesnn = nntrain(nn, train_x, train_y, opts);[er, bad] = nntest(nn, test_x, test_y);assert(er < 0.1, 'Too big error');%% ex4 neural net with sigmoid activation functionrand('state',0)nn = nnsetup([784 100 10]);nn.activation_function = 'sigm'; % Sigmoid activation functionnn.learningRate = 1; % Sigm require a lower learning rateopts.numepochs = 1; % Number of full sweeps through dataopts.batchsize = 100; % Take a mean gradient step over this many samplesnn = nntrain(nn, train_x, train_y, opts);[er, bad] = nntest(nn, test_x, test_y);assert(er < 0.1, 'Too big error');%% ex5 plotting functionalityrand('state',0)nn = nnsetup([784 20 10]);opts.numepochs = 5; % Number of full sweeps through datann.output = 'softmax'; % use softmax outputopts.batchsize = 1000; % Take a mean gradient step over this many samplesopts.plot = 1; % enable plottingnn = nntrain(nn, train_x, train_y, opts);[er, bad] = nntest(nn, test_x, test_y);assert(er < 0.1, 'Too big error');%% ex6 neural net with sigmoid activation and plotting of validation and training error% split training data into training and validation datavx = train_x(1:10000,:);tx = train_x(10001:end,:);vy = train_y(1:10000,:);ty = train_y(10001:end,:);rand('state',0)nn = nnsetup([784 20 10]); nn.output = 'softmax'; % use softmax outputopts.numepochs = 5; % Number of full sweeps through dataopts.batchsize = 1000; % Take a mean gradient step over this many samplesopts.plot = 1; % enable plottingnn = nntrain(nn, tx, ty, opts, vx, vy); % nntrain takes validation set as last two arguments (optionally)[er, bad] = nntest(nn, test_x, test_y);assert(er < 0.1, 'Too big error');```[![Bitdeli Badge](https://d2weczhvl823v0.cloudfront.net/rasmusbergpalm/deeplearntoolbox/trend.png)](https://bitdeli.com/free "Bitdeli Badge")

Java Memory Model & Computer Memory Model

Summary: Thevolatilekeyword can make sure that a given variable is read directly from main memory, and always written back to main memory when updated. A synchronized block guarantees that onl...

freeRoad 254

The Java Memory Model

The Java Memory Model This web page is a starting point for discussions of and information concerning the Java Memory Model (Chapter 17 of the Java Language Specification). The Java Memory Model

huaguoming的专栏 1299

【Java】Java Memory Model FAQ

Java的内存模型中某些“奇技淫巧”,或者说是“巫术”,对于某些特定场景是非常关键的。 从某种角度而言,我们可以直接称之为“缺陷”;“让语言的使用者无需关心底层实现”是编程语言发展的重要方向之一。“程序语义简单直观”也是 JSR 133 的目标之一。 如,JDK CopyOnWriteArrayList.set() 方法中对 volatile 字段的处理方式就涉及了非常晦涩的内存模型特性。(详...

一个被IT搞的 165

Understanding Java Memory Model

IntroductionIn this article I’m going to talk about java memory model(JMM for short). Java has been widely used in many areas and understanding JMM is the precondition of writing correct and efficient

刘人杰的博客 384
上一篇: Fedora Reset Password
下一篇: Web应用中Log4j与JNDI结合1 -- JNDI指定配置文件
开心的D哥
博客等级 码龄22年 63粉丝 110原创
评论
成就一亿技术人!
拼手气红包6.0元
还能输入1000个字符
 
 条评论被折叠 查看
添加红包

请填写红包祝福语或标题

个

红包个数最小为10个

元

红包金额最低5元

当前余额3.43元 前往充值 >
需支付:10.00元
成就一亿技术人!
领取后你会自动成为博主和红包主的粉丝 规则
hope_wisdom
发出的红包
实付元
使用余额支付
点击重新获取
扫码支付
钱包余额 0

抵扣说明:

1.余额是钱包充值的虚拟货币,按照1:1的比例进行支付金额的抵扣。
2.余额无法直接购买下载,可以购买VIP、付费专栏及课程。

余额充值