In IE 8 this behaviour has been changed in an attempt to reduce the number of processes allocated to IE. In previous versions of IE, clicking on the blue ‘e’ icon on the start menu would create a new IE frame window in a separate instance of the iexplore.exe process.
By default, the upper limit on the number of processes is based on the amount of physical memory available to Windows. Once the cap is reached, new tabs will share existing processes with other tabs. Initially, each new tab and pop-up window gets its own process but as the number of tabs grows the number of processes is capped. In IE 7, a separate frame window was created if you attempted to open tabs with different protection levels. One advantage of this model is that it allows tabs for both protected mode and non-protected mode web sites to be loaded into the same top level window.
Pop-up windows are treated in a similar way and will placed in separate processes if possible. IE 8 will even attempt to re-start and re-open an individual tab if a problem occurs. The IE frame window and tabs run in a separate processese, so that if one tab crashes you will not lose the whole of your browser session: IE 8 has a new feature known as Loosely Coupled IE (LCIE) that uses separate instances of the iexplore.exe process to provide enhanced isolation and reliability. If you are concerned about your web site’s performance make sure that you also check it in IE 7 as it may be substantially different from IE 8. Increasing the number of active connections to six (the same as Firefox 3.0) allows for much greater concurrently and drastically reduces the amount of blocked time experienced on most web pages: In HttpWatch, this is known as the Blocked time and is shown as a gray bar in the time chart. The limit of only two active connections would often cause requests to be queued up in IE until a connection became available. Here’s an example using HttpWatch and IE 7: In earlier versions of IE only a maximum of two connections would simultaneously download content from a single host name (e.g. #1 : IE 8 Opens More Connections Per Host NameĪs we previously mentioned in Blocked time and IE8, the default number of concurrent connections per host name has been increased in IE 8. We’ve been using IE 8 for just over two weeks and wanted to run through some of the significant differences that will affect anyone involved in web development, debugging or performance tuning.
0 kommentar(er)
