google chrome - How can I tell what javascript has been compiled when running V8 -


i have herd v8 compiles "hot code" optimise javascript performance. there way can tell code has been compiled , code has not?

first , foremost need profile code in profiles tab of javascript console in chrome see worth testing. if function, module, or whatever trying test not take time, won't worth effort.

v8's jit going make assumptions code, if assumptions true code lightning fast. if not v8 deoptimize code program continues. here instance own tests. in code below testing merge sort function had written.

console.time('order'); msort(ob); console.timeend('order');

the first run of 60000 random numbers completes after 8ms, , of following jump around 16ms. jit has issues wrote recompiled code. have seen exact opposite occur code jumps twice fast. if want @ it, not exact version, 1 using es6 module syntax. https://github.com/jamesrhaley/es2015-babel-gulp-jasmine/blob/master/src/js/mergesort/mergesort.js

also if code not worth optimizing, won't optimized begin with. here couple of links helped me improve speed when writing js.

https://www.youtube.com/watch?v=ujpdhx5ztaw

https://www.smashingmagazine.com/2012/11/writing-fast-memory-efficient-javascript/#so-how-does-javascript-work-in-v8


Comments

Post a Comment

Popular posts from this blog

get url and add instance to a model with prefilled foreign key :django admin -

Image
i have page in each contest shown in row. each row contains contest id , link other model names have foreign key contest. news model: class news(models.model): title = models.charfield(max_length=50, null=true) description = models.textfield() time = models.timefield( default= datetime.datetime.now().time()) contest = models.foreignkey(contest) i want use admin adding , changing these models. want when user clicks on 'news' has foreign key contest id=1, shows list of news value foreign key. use {% instance in instances %} <tr class="{% cycle 'row1' 'row2' %}"> <td>{{ instance.title }}</td> <td>{{ instance.starttime }}</td> <td>{{ instance.timespan }}</td> <td>{{ instance.date }}</td> <td><a href="/adm...
Read more

android - Keyboard hides my half of edit-text and button below it even in scroll view -

i having trouble keyboard covers edit-text , half of button in scroll view. here's layout , please tell me how should resolve problem. many questions on topic none of them s working me. <?xml version="1.0" encoding="utf-8"?> <linearlayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:background="@drawable/bg" android:layout_height="match_parent"> <scrollview android:layout_width="match_parent" android:fillviewport="true" android:layout_height="match_parent"> <relativelayout android:layout_width="match_parent" android:layout_height="wrap_content" android:orientation="vertical"> <linearlayout android:layout_width="match_parent" android:layout_height="w...
Read more

css - Make div keyboard-scrollable in jQuery Mobile? -

from can tell, although jquery-mobile-powered pages can contain divs overflow set scroll or auto, , these divs can scrolled one-screen bar or mouse wheel, cannot scrolled using arrow keys, page-up/page-down, or home/end. instead, official "page" div (with data-role="page") absorbs input. perhaps other divs can't acquire focus, i'm not sure. is there way around this? edit: jsfiddle of simple example: https://jsfiddle.net/qogz0shx/ <script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.4/jquery.min.js"></script> <script src="https://ajax.googleapis.com/ajax/libs/jquerymobile/1.4.5/jquery.mobile.min.js"> </script> <link rel="stylesheet" href="https://code.jquery.com/mobile/1.4.5/jquery.mobile-1.4.5.css"/> <style> #outer { overflow:scroll; height: 50vh; width: 50vw; } #inner { height: 500vh; width: 500vw; } ...
Read more