“Packet Sniffers”
When I sit down to analyze a web site, I start by looking at the HTTP requests for the web page in question. This makes it possible to identify the slow parts of the page. A packet sniffer that is handy and easy to use is the first tool to add to your kit. The tools included in this category are HttpWatch, Firebug Net Panel, AOL Pagetest, VRTA, IBM Page Detailer, Web Inspector Resources Panel, Fiddler, Charles, and Wireshark.

“Web Development Tools”
Page performance isn’t just about load time—JavaScript, CSS, and DOM structure play a significant role, especially for Web 2.0 applications. Web development tools provide inspectors, profilers, and debuggers for analyzing web page behavior. This section includes Firebug, Web Inspector, and IE Developer Toolbar.


“Performance Analyzers”
Performance analyzers evaluate a given web page against a set of performance best practices. As I will explain, they vary a great deal in what they measure. This section describes YSlow, AOL Pagetest, VRTA, and neXpert.


“Miscellaneous”
This section includes a grab bag of tools I use regularly: Hammerhead, Smush.it, Cuzillion, and UA Profiler.

 

Others:

 HP: 
    LoadRunner
    Diagnostics
    SiteScope
    Business Availability Center
 
 Compuware:
    QALoad
    Server Vantage
    Application Vantage
    Client Vantage
    Network Vantage
    Vantage Analyzer
 
 Spirent:
    SmartBits