### UPDATE ###
After more tests and a closer look at the ApacheBench sources, we now know that this problem stems from a race condition in ApacheBench.
### END UPDATE ###
I reported this to the AWS authors, who came back with this response:
This looks very very bad and does not correspond to any experience I have had with AWS. I’m really concerned by these results. How does your AWS server look like?
Luckily I’d tested this using both my homegrown AWS powered web-framework, and the demos/hello_world example from the AWS source package. Both exhibit the same behavior.
I did some more tests, this time using both 32 and 64 bit systems, and I even threw in a virtualized Slackware (VirtualBox 3.2.12) for completeness. I then reported back to the AWS maillist.
This is a very odd issue indeed, and I truly hope the AWS developers can figure out the what and why, but until that happens, I’ll soldier on. AWS is no less of a marvelous piece of software because of this minor glitch.