Disclaimer: The article below discusses pre-release features and performance numbers. Some of these features could change on the RTM version. Also, the actual performance numbers could change from now until we ship.
During .Net 4.5 development we tried to improve the performance of ASP.NET in shared hosting scenarios, where many web sites might share the same machine. In such environment traffic is usually low. In this case startup time becomes very important. That is the time it takes a web site to receive a first request and respond to it, when the worker process was down, and the web site was already compiled, which is the most common case. Also assuming that other worker processes are running other web sites, so shared components will be already loaded.
Another important metric is the site density. The more sites we can fit in a box the lower the cost for the hosters. The site metric we used was the unshared working set. That is the total working set minus the shared working set.
The first thing we needed to validate our work was a set of scenarios that could allow us to measure our progress, through this two metrics: Startup and Site Density. We decided to use community created and used web applications. We gathered a bunch of applications deployed by the Web Platform Installer (Web PI).
We focused on three applications: DotNetNuke, Blogengine and IBuySpy+*. The decision was based on our planned work, which included features that will deal with assemblies in the Bin folder. So we picked three apps that have different levels of Bin folder use. DotNetNuke has heavy use of assemblies in the Bin folder, Blogengine has some use and IBuySpy+ has none.
We added several features during this product cycle to improve startup time. These features are the results of the work of several teams at Microsoft, including CLR and Windows Server. ASP.NET team worked on enabling these features in our product. The feature list is below:
The features implemented to aid the memory site were:
Baseline: Windows 2008 R2, .Net 4.0
Results: Windows 8 Server, .Net 4.5
Unshared Working Set
Colds Startup Time
<Processor Num="2">Intel(R) Xeon(R) CPU 5160 @ 3.00GHz</Processor>
<HardDrive>HP DF146ABAA9 SCSI Disk Device SCSI[136.73 GB]</HardDrive>
<HardDrive>SEAGATE ST3300656SS SCSI Disk Device SCSI[279.39 GB]</HardDrive>
Other resources for the features implemented:
*IBuySpy+ is a variation of the IBuySpy (a web app we use extensively on the ASP.NET perf team), which added some of the new features of ASP.NET/.Net framework added during the v3.5 timeframe.