ASP.NET application on IIS7 - very slow startup after iisreset

Question

I have an ASP.NET 3.5 website running under IIS7 on Windows 2008.

When I restart IIS (iisreset), then hit a page, the initial startup is really slow.

I see the following activity in Process Explorer:

• w3wp.exe spawns, but shows 0% CPU activity for about 60 seconds
• Finally, w3wp.exe goes to 50% CPU for about 5 seconds and then the page loads.

I don't see any other processes using CPU during this time either. It basically just hangs.

What's going on during all that time? How can I track down what is taking all this time?

Answer 1

I found that there was a network delay making an initial connection from the front end web server to the database server.

The issue was peculiar to Windows 2008 and our specific network hardware.

The resolution was to disable the following on the web servers:

• Chimney offload state

• Receive window auto-tuning level