What this tells us is that for a normal mix of traffic, the weighted average memory consumption per request is 12.36MB. So if you had a web server that had 1GB of RAM, and you were reserving 200MB for the operating system, etc., then the amount of memory left over for the application would be 800MB. Dividing this value by the weighted average gives 800/12.36 = 64.72. This is the number of concurrent requests in the top ten that you can process at the same time without running the risk of exhausting memory and causing the system to swap.
It should be noted that we have used the top ten here as a general rule of thumb. If you find that the percentage of requests for your URLs has not fallen off to a small number—say, 1 percent—at the end of your table, then you may need to extend the table to include a larger number of URLs. ApacheTop automatically ignores any query string parameters after a URL when creating its sorted-by-request view, so variations in the
URLs due to query strings won’t create a lot of extra entries. The intention is not to provide a 100 percent accurate assessment for all of the possible URLs in your system, which could run to many hundreds of pages on a large site, but to rather to provide sufficient coverage of the major paths.