Java GC log analysis tools

1. GCViewer
   Free open source tool to visualize data produced by the Java VM options -verbose:gc and -Xloggc:<file>. It also calculates garbage collection related performance metrics (throughput, accumulated pauses, longest pause, etc.).
   Development stopped in 2008.
2. Fork of original GCViewer
   Supports Java 1.7. Github, 'nuff said.
3. Garbage Cat
   Garbage Cat parses Java garbage collection logging and provides analysis to support JVM tuning and troubleshooting for OpenJDK and Sun JDK. It differs from other tools in that it goes beyond the simple math of calculating statistics such as maximum pause time and throughput. It adds context to these numbers by identifying the associated collector or collector phase, which allows for much deeper insight and analysis. This is especially relevant to collectors such as the Concurrent Mark Sweep collector that have multiple concurrent and stop-the-world phases.
4. IBM GCMV
   IBM Monitoring and Diagnostic Tools for Java - Garbage Collection and Memory Visualizer (GCMV) provides analysis and views of your applications verbose gc output. GCMV displays the data in both graphical and tabulated form. It provides a clear summary and interprets the information to produce a series of tuning recommendations.
   Installed within the IBM Support Assistant Workbench.
5. jClarity Censum
   Censum is an intelligent tool that takes log files from the complex Java™ (JVM) garbage collection sub-system and gives you meaningful answers. 14-day free trial.

IE document/browser modes

http://jsfiddle.net/7ZE7M/

IE9:
http://i.stack.imgur.com/yzXVq.png

IE10:

• navigator.appName: Microsoft Internet Explorer
• navigator.userAgent: Mozilla/5.0 (compatible; MSIE 10.0; Windows NT 6.1; WOW64; Trident/6.0; SLCC2; .NET CLR 2.0.50727; .NET CLR 3.5.30729; .NET CLR 3.0.30729; Media Center PC 6.0; .NET4.0C; .NET4.0E)
• document.compatMode: CSS1Compat
• document.documentMode: 10

IE11:

• navigator.appName: Netscape
• navigator.userAgent: Mozilla/5.0 (Windows NT 6.1; WOW64; Trident/7.0; SLCC2; .NET CLR 2.0.50727; .NET CLR 3.5.30729; .NET CLR 3.0.30729; Media Center PC 6.0; .NET4.0C; .NET4.0E; rv:11.0) like Gecko
• document.compatMode: CSS1Compat
• document.documentMode: 11

Interesting thoughts

• Amusingly, the history of the evolution of C++ over time can be described as a history of trying to plug the leaks in the string abstraction. Why they couldn't just add a native string class to the language itself eludes me at the moment.
  Joel Spolsky, http://www.joelonsoftware.com/articles/LeakyAbstractions.html
• Organizations are constrained to produce designs which are copies of the communication structures of these organizations. If you have four groups working on a compiler, you'll get a 4-pass compiler.
  Melvin Conway, http://en.wikipedia.org/wiki/Conway's_law
• When I wrote this, only God and I understood what I was doing. Now, God only knows.
  Karl Weierstrass, http://stackoverflow.com/a/316233/1235394
• The big ground shaker is Version 11 of Microsoft Explorer. And it has an amazing string including the words "like Gecko" in it. Apparently, MS ran into problems of page rendering when they tried to use version 11 (think of all those browser detection scripts return version 1 by jove).
  http://www.zytrax.com/tech/web/browser_ids.htm
• One fun thing about concurrency is that the more you increase a concurrent process’s efficiency, the more likely you are to discover its buried race conditions and deadlocks. 5 Another fun thing is that eliminating one race condition will make smaller, more obscure race conditions more likely to bite you.
  http://blog.npmjs.org/post/98131109725/npm-2-0-0

Максимальная длина массива в Function.prototype.apply

MDN предупреждает, что максимальная длина массива, передаваемая в Function.prototype.apply, ограничена (порядка 10^4). Меня заинтересовали точные значения, которые я определяю вот таким скриптом.

Глубина стека JavaScript в разных браузерах

Скрипт для измерения глубины стека и результаты (получены на одном компьютере, Windows 7 SP1, 64-bit):

Chrome 28:      20966 - 21000, не зависит от количества открытых вкладок
Firefox 20:     26000 - 50000, сильно изменяется от измерения к измерению
Firefox 22:     38000 - 53000, сильно изменяется от измерения к измерению
Opera 12.16:    32629, не зависит от количества открытых вкладок
Opera 15:       20968, не зависит от количества открытых вкладок
IE10:            2946 - 2947, не зависит от количества открытых вкладок, включения/выключения отладки JavaScript, выбора Browser Mode/Document Mode
IE9 (IETester): 20670, не зависит от количества открытых вкладок

IE8 (IETester):  1472 - 1475, не зависит от количества открытых вкладок

IE7 (IETester):  2546 - 2548, не зависит от количества открытых вкладок

IE6 (IETester):  2546 - 2548, не зависит от количества открытых вкладок

Результаты для IE на разных компьютерах различаются на два порядка, на одной из машин в IE9 была получена глубина стека 42329, на другой для IE8 (IE9 downgraded to IE8) было всего 276 (!).

UnderGet - Download Blocked Files

UnderGet - Download Blocked Files
UnderGet allows you to download files that are otherwise blocked by a firewall or other tool at your work, school or country.
UnderGet can bypass blocks that prevent you from downloading files based on their file type, extension or content by renaming the file or encoding its content so the blocking software can not detect it.

Hardware acceleration flags in Firefox

1. Open about:config tab
2. Search for azure
   gfx.canvas.azure.backends direct2d,skia,cairo
   gfx.content.azure.backends direct2d
   gfx.content.azure.enabled true
3. Search for direct2d (Windows)
   gfx.direct2d.disabled false
4. Search for directwrite
   gfx.font_rendering.directwrite.enabled true
5. Search for layers
   layers.acceleration.disabled false
   layers.acceleration.draw-fps false
   layers.acceleration.force-enabled false
   layers.async-video.enabled false
   layers.composer2d.enabled false
   layers.offmainthreadcomposition.animate-opacity false
   layers.offmainthreadcomposition.animate-transform false
   layers.offmainthreadcomposition.log-animations false
   layers.prefer-d3d9 false
   layers.prefer-opengl false
6. Also check for gfx.content

Acceleration test
CSS 3D demo