Apache Benchmark Document Length vs YSlow Page's Total Weight

I'm load testing my page with Apache Benchmark:

ab -n 20 -c 5 http://localhost/mysite/index/index

I know that Document Length stands for the 开发者_StackOverflow社区sum of all HTML images,CSS,JS and anything within the response in bytes.

If I go over Firefox and I run YSlow I see that:

The page has a total of 22 HTTP requests and a TOTAL WEIGHT of 202.7K bytes 
with empty cache

• what's the difference between the document length size and the YSlow page's total weight?

I'd love to know where these definitions (AB/YSlow) differ so that (maybe) I can understand why my AB document length is so high (up to 14000 bytes) compared to other websites (with similar contents, e.g. grubwithus.com) that have a document length not exceeding 91 bytes! However, I also noticed that the YSlow size of my webpage is a way less than the compared size of grubwithus.com (202k against 1124k).

YSlow counts all linked resources as well (all linked files, from styles, scripts, images up to these crappy flashes and probably even PDFs if they are embedded). ab just pulls the HTML document (at least for the version I know of, which seems to be outdated).

Next to that I think ab gives you the uncompressed sizes but yslow the compressed ones. But I'm no so into yslow to be sure on this. Check their docs for specifics.

Generally both tools do something different. So don't compare their size infos. Ab is for generating load on the server, YSlow is to analyze the nature of the isolated response in context of a webbrowser.