Which version of Gatling 1 did you use when it used to work?
Gatling 1.5.3. Even with that I didn’t try running more than 20 users. So not sure if the problem exists in 1.5.3 or not.
Could you give it a try with 1.5.3, please? If there’s a problem on Gatling side, it lies deep into Netty, and that’s not somewhere I like investigating…
Actually, are you sure you’re not saturating your NIC?
Also, which JDK do you use?
java version "1.6.0_27"
OpenJDK Runtime Environment (IcedTea6 1.12.6) (6b27-1.12.6-1ubuntu0.10.04.4)
OpenJDK Server VM (build 20.0-b12, mixed mode)
We have a 100 MB network between the client and the server and I'm
pretty sure we're not saturating our NIC. When we run 18 to 20
concurrent files (Average file sizes: 14 MB), it might slow down and
get high response times, but not just die abruptly
Vivek
I checked the AHC code and had a chat with the author, Jean-François Arcand: this is plain NIO code, so the problem might be a JVM NIO implementation bug.
Your JDK is quite old (more than 2,5 year old), so could you try upgrading? Could you also try switching from OpenJDK to Hotspot?