Joshua Slive wrote: >>From: Brian Pane [mailto:[EMAIL PROTECTED]] >> > >>>Can you really benchmark speed differences between the two? >>> >>Yes. And the difference is quite large. >> > >You've tried out Apache with the two different methods of exclusion and >found that the LogExclude method results in a server that can serve >significantly more traffic? I'm surprised! >
My methodology was to extract the cost of the regex and hash lookup operations from the profile data from the current httpd and compute the relative cost of the two mechanisms based on those (my last message describes the data in a bit more detail). >>I'm mildly alarmed that we're actually advocating it as a general-purpose >>solution in the documentation URLs listed above; we really should warn >>readers that the processing cost scales linearly with the number of rules. >> > >There are many directives in apache that work like this, including >name-virtual hosts, Redirects, Aliases, etc. > If I remember correctly, the name-based virtual hosts have been fixed so that they aren't O(N). Redirects and Aliases are O(N), though, which is why we don't use them too liberally on high-traffic servers. > My guess is that for 99% of >cases, all these things put together are lost in the backround noise of >disk/network speed. > Depends on what metric you're looking at. If you look at delivery speed as measured on the client, the network tends to hide the impact of CPU-bound inefficiencies. But from a data center cost perspective, a much more important metric is how much CPU time you're burning per request. An n% increase in CPU utilization per request translates pretty linearly into increased hardware cost. --Brian
