Dynamic pages (created with Perl/PHP/... on the fly) rarely have the exact same byte length for the same URL. Apachebench (src/support/ab), however, registers this as an error during benchmarking and prints a misleading - and very high - number of "length errors". I wrote a 5-minute patch that implements a "nolength" command-line switch to suppress these length errors; I will attach it to this bug report as soon as I can find the proper button. :)
Created attachment 10937 [details] adds variable document length command-line option to apachebench
I think it would make more sense not to count varying length resonses as failures at all. A failure would be to have a header Content-Length different from the actual length of the response body.
*** Bug 42040 has been marked as a duplicate of this bug. ***
*** Bug 9945 has been marked as a duplicate of this bug. ***