Greetings

mayers — Wed, 13 Dec 2006 22:01:00 GMT

Hi, all & welcome to the Windows Performance Blog. My name is Matt Ayers and I’m a Program Manager on the Windows Client Performance team. I occasionally write about Windows but I always seem to fall into the ‘always a blogs-maid, never a blogger' category – most recently, I borrowed some space from Tom Archer to talk about ReadyBoost. Well... we've decided to create a perf team blog to talk about key features, technical analysis and other topics near & dear to our hearts. We'll try and have a new topic every few weeks - if there's something you'd like us to talk about, please mail wprfblog@microsoft.com.

Anyhow, to jump right in, let’s chat about one of our major goals for Windows Vista: consistent responsiveness. General customer feedback about XP is that the OS performs pretty well, most of the time… but not necessarily all the time. We found that this inconsistent performance stems from having the wrong data is in memory; put another way, the memory is in a cold state. The most well known cold state occurs right after you start the system but there are many other ways that the system can get ‘cold’.

Another common example would be switching back to an application, such as a web browser after running several other applications or even a single application with a large data set like a video editor or a 3D game. If the machine doesn’t have enough memory to hold all of the other applications plus the browser, then some of the code and data for it will be re-loaded from of disk. For Windows Vista we focused on eliminating more cases where the system performed inconsistently. This is a continuation of work we did in XP which improved application launches.

Our innovations in memory management deliver the core of these improvements. In Windows Vista, SuperFetch* pays attention to what data the user needs and when they need it. Based on this history, it identifies data that are likely to be most useful to the user and proactively places them in memory before the user actually requests them. Additionally, SuperFetch will use this knowledge to keep important pages in memory, even if they haven’t been used for a while.

Anyhow, a detailed discussion of SuperFetch will be better served by its own post in the future – for now, I want to use it as an example of a feature that we use to improve the responsiveness of Vista. SuperFetch, along with ReadyBoost, low-priority I/O and loads of analysis has allowed us to add new features to Vista and improve the overall responsiveness of the OS.

Over the next few weeks, I’ll discuss these features, as well as the best way to measure their impact on the OS. So thanks & stay tuned.

-M

*trivia: this is the ‘mystery feature’ referred to in one of Richard Russell's 'pigs can fly' posts

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Greetings