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  • <!... <head> <meta charset="utf-8"> ...meta name="viewport" content="width=device-width, initial-scale=1">... 不过它对于那些可以不依赖任何脚本或不被任何脚本依赖的脚本来说却是非常合适的,最...
  • Performance Modeling

    2016-10-21 13:32:12
    Engineer for performance up front.Manage performance risks.Map business requirements to performance objectives.Balance performance against other quality-of-service requirements.Identify

    Objectives

    • Engineer for performance up front.
    • Manage performance risks.
    • Map business requirements to performance objectives.
    • Balance performance against other quality-of-service requirements.
    • Identify and analyze key performance scenarios.
    • Identify and allocate budgets.
    • Evaluate your model to ensure you meet your performance objectives.
    • Identify metrics and test cases.

    Performance modeling provides several important benefits:

    • Performance becomes part of your design.
    • Modeling helps answer the question "Will your design support your performance objectives?" By building and analyzing models, you can evaluate tradeoffs before you actually build the solution.
    • You know explicitly what design decisions are influenced by performance and the constraints performance puts on future design decisions. Frequently, these decisions are not captured and can lead to maintenance efforts that work against your original goals.
    • You avoid surprises in terms of performance when your application is released into production.
    • You end up with a document of itemized scenarios that help you quickly see what is important. That translates to where to instrument, what to test for, and how to know whether you are on or off track for meeting your performance goals.

    Upfront performance modeling is not a replacement for scenario-based load testing or prototyping to validate your design. In fact, you have to prototype and test to determine what things cost and to see if your plan makes sense. Data from your prototypes can help you evaluate early design decisions before implementing a design that will not allow you to meet your performance goals.

    To use this performance model, do the following:

    • Set goals. Capture whatever partial performance-related information you have, including your application prototype's metrics, important scenarios, workloads, goals, or budgets. The performance model presented in this chapter is designed to use the partial information you might have in these areas as input. You do not have to completely fill out the data or have a complete understanding of your own requirements and solutions.
    • Measure. Execute the suggested tasks in the process to iteratively set goals and measure the result of your action, by using the partially completed model as a guide of what to focus on. This allows you add and refine the information in your model. The new data will inform the next round of goal setting and measurement.

    Why Model Performance?

    A performance model provides a path to discover what you do not know. The benefits of performance modeling include the following:

    • Performance becomes a feature of your development process and not an afterthought.
    • You evaluate your tradeoffs earlier in the life cycle based on measurements.
    • Test cases show you whether you are trending toward or away from the performance objectives throughout your application life cycle.

    Modeling allows you to evaluate your design before investing time and resources to implement a flawed design. Having the processing steps for your performance scenarios laid out enables you to understand the nature of your application's work. By knowing the nature of this work and the constraints affecting that work, you can make more informed decisions.

    Your model can reveal the following about your application:

    • What are the relevant code paths and how do they affect performance?
    • Where do the use of resources or computations affect performance?
    • Which are the most frequently executed code paths? This helps you identify where to spend time tuning.
    • What are the key steps that access resources and lead to contention?
    • Where is your code in relation to resources (local, remote)?
    • What tradeoffs have you made for performance?
    • Which components have relationships to other components or resources?
    • Where are your synchronous and asynchronous calls?
    • What is your I/O-bound work and what is your CPU-bound work?

    And the model can reveal the following about your goals:

    • What is the priority and achievability of different performance goals?
    • Where have your performance goals affected design?
    Detail please refer to:

    https://msdn.microsoft.com/en-us/library/ff647767.aspx



    展开全文
  • Image Classification Performance Table

    万次阅读 2019-12-14 13:42:58
    Performance Table For simplicity reason, I only listed the best top1 and top5 accuracy on ImageNet from the papers. Note that this does not necessarily mean one network is better than another when the...

    Performance Table

    For simplicity reason, I only listed the best top1 and top5 accuracy on ImageNet from the papers. Note that this does not necessarily mean one network is better than another when the acc is higher, cause some networks are focused on reducing the model complexity instead of improving accuracy, or some papers only give the single crop results on ImageNet, but others give the model fusion or multicrop results.

    • ConvNet: name of the covolution network
    • ImageNet top1 acc: best top1 accuracy on ImageNet from the Paper
    • ImageNet top5 acc: best top5 accuracy on ImageNet from the Paper
    • Published In: which conference or journal the paper was published in.
    ConvNet ImageNet top1 acc ImageNet top5 acc Published In
    Vgg 76.3 93.2 ICLR2015
    GoogleNet - 93.33 CVPR2015
    PReLU-nets - 95.06 ICCV2015
    ResNet - 96.43 CVPR2015
    PreActResNet 79.9 95.2 CVPR2016
    Inceptionv3 82.8 96.42 CVPR2016
    Inceptionv4 82.3 96.2 AAAI2016
    Inception-ResNet-v2 82.4 96.3 AAAI2016
    Inceptionv4 + Inception-ResNet-v2 83.5 96.92 AAAI2016
    RiR - - ICLR Workshop2016
    Stochastic Depth ResNet 78.02 - ECCV2016
    WRN 78.1 94.21 BMVC2016
    SqueezeNet 60.4 82.5 arXiv2017(rejected by ICLR2017)
    GeNet 72.13 90.26 ICCV2017
    MetaQNN - - ICLR2017
    PyramidNet 80.8 95.3 CVPR2017
    DenseNet 79.2 94.71 ECCV2017
    FractalNet 75.8 92.61 ICLR2017
    ResNext - 96.97 CVPR2017
    IGCV1 73.05 91.08 ICCV2017
    Residual Attention Network 80.5 95.2 CVPR2017
    Xception 79 94.5 CVPR2017
    MobileNet 70.6 - arXiv2017
    PolyNet 82.64 96.55 CVPR2017
    DPN 79 94.5 NIPS2017
    Block-QNN 77.4 93.54 CVPR2018
    CRU-Net 79.7 94.7 IJCAI2018
    ShuffleNet 75.3 - CVPR2018
    CondenseNet 73.8 91.7 CVPR2018
    NasNet 82.7 96.2 CVPR2018
    MobileNetV2 74.7 - CVPR2018
    IGCV2 70.07 - CVPR2018
    hier 79.7 94.8 ICLR2018
    PNasNet 82.9 96.2 ECCV2018
    AmoebaNet 83.9 96.6 arXiv2018
    SENet - 97.749 CVPR2018
    ShuffleNetV2 81.44 - ECCV2018
    IGCV3 72.2 - BMVC2018
    MnasNet 76.13 92.85 CVPR2018
    SKNet 80.60 - CVPR2019
    DARTS 73.3 91.3 ICLR2019
    ProxylessNAS 75.1 92.5 ICLR2019
    MobileNetV3 75.2 - arXiv2019
    Res2Net 79.2 94.37 arXiv2019
    展开全文
  • performance-timing

    2018-08-14 11:58:44
    performance的兼容性 performance.timing对应时间节点 performance的获取方式 window.performance performance.timing的常用监测时间 DNS解析时间: domainLookupEnd - domainLookupStart TCP建立连接...

    performance的兼容性

    这里写图片描述

    performance.timing对应时间节点

    这里写图片描述
    这里写图片描述

    performance的获取方式

    window.performance

    performance.timing的常用监测时间

    • DNS解析时间: domainLookupEnd - domainLookupStart

    • TCP建立连接时间: connectEnd - connectStart

    • 白屏时间: responseStart - navigationStart

    • dom渲染完成时间: domContentLoadedEventEnd - navigationStart

    • 页面onload时间(首屏时间): loadEventEnd - navigationStart

    详细可看Navigation Timing获取页面加载各个阶段所需时间

    展开全文
  • performance的使用

    2021-02-19 16:00:36
    performance工具的使用performance任务管理器performance工具内存的变化TimeLineGC回收堆块照查找分离DOM performance performance是一种用于监控浏览器运行的时候性能变化的工具,他可以帮助我们观察页面运行时内存...

    performance

    performance是一种用于监控浏览器运行的时候性能变化的工具,他可以帮助我们观察页面运行时内存的变化,渲染的时长;并分析需要改进优化的地方。

    任务管理器

    通过shift+esc,我们可以调出浏览器的任务管理器。通过任务管理器我们可以观察页面的

    • 内存占用空间
    • cpu使用率
    • 网络情况
    • 进程ID

    在这里插入图片描述
    这里我们使用较多的时内存的占用以及cpu的消耗,任务管理器可以实时的查看内存空间的占用,但缺点是,无法看到页面的内存空间占用的趋势图,没有办法很好的分析内存的使用情况

    performance工具

    在这里插入图片描述

    • 打开控制台(按f12,或打开开发者工具)

    • 点击performance

    • 点击小圆点就可以开始记录页面运行的情况
      在这里插入图片描述

    • 点击stop可以停止记录,并分析运行的情况
      在这里插入图片描述

    内存的变化TimeLine

    打开memory,可以看到页面在运行的时候内存的随时间的变化趋势图,红色框标识的地方就是内存的变化,通过这个变化我们就知道什么时候在哪里的内存消耗不合理或者有异常,并对代码进行优化
    在这里插入图片描述

    GC回收

    GC在运行的时候,应用程序是停止的,所以频繁的GC会导致程序假死,导致用户有明显的使用卡顿。

    我们可以从TimeLine去判断什么时候进行GC回收操作

    当存在频繁的内存升高和下降的时候,就说明有频繁的GC回收操作,这是不合理的,也是需要优化的地方
    在这里插入图片描述

    堆块照查找分离DOM

    首先我们得理解什么是分离DOM,DOM有三种形式

    • 存在于DOM树中的DOM元素
    • 垃圾DOM:不存在于DOM树,且没有被引用的DOM元素
    • 分离DOM:不存在于DOM树,但被引用的DOM元素

    分离DOM会导致DOM无法被回收,从而造成内存泄漏,通过堆块照的方式,我们可以找到代码中的分离DOM,并进行优化

    实例代码

    <!DOCTYPE html>
    <html lang="en">
    <head>
      <meta charset="UTF-8">
      <meta http-equiv="X-UA-Compatible" content="IE=edge">
      <meta name="viewport" content="width=device-width, initial-scale=1.0">
      <title>分离DOM</title>
    </head>
    
    <body>
      <button id="addDom">addDom</button>
      <script>
        let dom = null
        document.querySelector('#addDom').onclick = function (e) {
        	// 点击按钮的时候,会新建一个dom元素,并保存在全局,但不插入DOM树内,这时就会产生一个分离dom
          dom = document.createElement('div')
        }
    
      </script>
    </body>
    </html>
    

    图解
    在这里插入图片描述
    在这里插入图片描述

    疑问
    GC回收操作是在一定的时间段内执行,还是当发现内存不足的时候再执行,或是其他?

    注:本文章主要是对学习知识进行总结,如有不同观点欢迎讨论

    展开全文
  • JS:Performance

    2021-01-13 15:05:26
    Performance 接口可以获取到当前页面中与性能相关的信息。它是 High Resolution Time API 的一部分,同时也融合了 Performance Timeline API、Navigation Timing API、 User Timing API 和 Resource Timing API。 ...
  • Performance Testing

    千次阅读 2015-05-20 09:10:51
    What is performance testing? It is a type of non-functional testing. Performance testing is testing that is performed, to determine how fast some aspect of a system performs under a particular workloa
  • window.performance

    千次阅读 2017-05-27 14:04:42
    在chrome控制台执行window.performance,会出现下面结果: 简单介绍performance中的属性: memory:{ jsHeapSizeLimit: 1136000000 // 内存大小限制 totalJSHeapSize: 16100000 // 可使用的内存 ...
  • 初识Chrome Performance

    千次阅读 2018-08-22 19:10:38
      Chrome Performance工具文章网上一搜一大把,但是作为一个刚入门的前端小白,我还是觉得自己整理一下(抄的),来加深理解。   网上很多文章都是使用官网提供的DEMO了进行分析的。大概看了一下该网站用例,...
  • Systems Performance:Enterprise and the Cloud

    千次下载 热门讨论 2015-06-20 22:20:32
    The accelerating deployment of large-scale web, cloud, Big Data, and virtualized computing systems has introduced serious new challenges in performance optimization. Until now, however, little ...
  • Guideline 2.3.1 - Performance

    千次阅读 2019-07-02 09:35:55
    Guideline 2.3.1 - Performance We discovered that your app contains hidden features. Attempting to hide features, functionality or content in your app is considered egregious behavior and can lead to r...
  • Performance Trace

    2015-01-19 17:33:27
    Runtime analysis of ABAP ...Performance Trace is a powerful tool for analyzing the runtime of ABAP programs. It enables you to record a program runtime for the following operations: database ac
  • ANTS Performance Profiler

    2018-12-18 18:47:53
    ANTS Performance Profiler  .NET性能调优之一:ANTS Performance Profiler的使用   https://documentation.red-gate.com/amp8/working-with-profiling-results/the-summary-page ...
  • BPF Performance Tools: Linux and Application Observability:源代码参加https://github.com/brendangregg/bpf-perf-tools-book
  • 详解谷歌浏览器 performance 选项卡

    万次阅读 多人点赞 2020-01-16 16:12:41
    本文要点:详细介绍谷歌浏览器 performance 选项卡的各个要素,让你知道如何查看网页性能。
  • Chrome Devtool — Performance

    千次阅读 2020-02-25 16:20:49
    Performance 一个在前端开发领域中,无法被忽视的存在。使用Chrome DevTools的performance面板可以记录和分析页面在运行时的所有活动。本文将详细介绍如何使用performance面板解决性能瓶颈。 一、Performance 工具...
  • MYSQL performance schema详解 0、performance_schema的介绍 ​ MySQL的performance schema 用于监控MySQL server在一个较低级别的运行过程中的资源消耗、资源等待等情况。 ​ 特点如下: ​ 1、提供了一种在...
  • Dynamic Performance Views

    千次阅读 2013-10-20 16:19:17
    Dynamic Performance Views
  • Java Performance Optimization

    千次阅读 2015-08-02 17:07:51
    Java Performance Optimization From:https://dzone.com/refcardz/java-performance-optimization Introduction Java is among the most widely used programming languages in the sof
  • 详解网页性能参数 performance API

    千次阅读 2020-01-13 16:52:16
    本文要点: 1. 介绍浏览器核心工作流程; 2. 介绍 performance 对象及方法。通过 performance 对象详解网页各项资源耗时及内存占用情况(精确到每个资源的DNS 解析时间,TCP连接时间等)。
  • Windows Performance Analyzer

    千次阅读 2015-02-04 18:01:17
    Windows Performance Analyzer Quick Start The Windows Performance Analyzer tools are designed to measure and analyze Windows system and application performance. The Performance Analyzer tools c
  • 2. 1 PERFORMANCE: APP COMPLETENESS Performance - 2.1 We were unable to review your app as it crashed on launch. We have attached detailed crash logs to help troubleshoot this issue. 情况不一,...
  • Linux Performance Tools

    千次阅读 2018-11-19 20:57:19
    copy: ... Linux Performance hi-res: observability + static + perf-tools/bcc (svg) slides: observability slides: static, benchmarking, tuning sar, perf-tools,...
  • selenium 记录 performance日志

    千次阅读 2019-09-05 09:06:53
    做爬虫的时候,有时候遇到需要的数据在加载资源当中,...而访问performance,可以获得加载网站时的资源请求信息,可以通过这一特点,获取url和数据。 import time from selenium import webdriver from seleniu...
  • 《system performance:Enterprise and the Cloud》&《BPF PerformanceTools》,性能调优大神Brendan Gregg写的两本书。前者
  • Performance Dashboard

    千次阅读 2010-10-19 17:17:00
    <br />如果你到现在为止使用过一段时间的SQLServer2005,那么当我提到SQLServer2005性能工具Performance Dashboard时,你也许不知道我说的什么。不,你是否过度疲劳使你丧失了信心而忘记了列入SQLServer2005的...
  • WET Dilutes Performance Bottlenecks

    千次阅读 2015-07-14 09:52:38
    WET Dilutes Performance BottlenecksKirk PepperdineTHE IMPORTANCE OF THE DRY PRINCIPLE (Don’t Repeat Yourself) is that it codifies the idea that every piece of knowledge in a system should have a ...
  • dma_performance_demo

    热门讨论 2014-08-06 23:29:26
    Bus Master DMA Performance Demonstration Reference Design for the Xilinx Endpoint PCI Express® Solutions
  • SQL Server Performance 分析

    万次阅读 2016-05-03 21:31:57
    对网络上的一篇博客做下笔记,适当扩展下对 Performance 各个涉及到的要素。这篇文章讲的是分析性能,老外写的: How to analyse SQL Server performance 主要的要点有这些: · How does SQL Server work · ...

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