Performance drop when targeting two agents on single IIS

*Setup as following: *

IIS

• Two application pools
• Two folders with resources (same structure)

Agents

• Agent1 -> 64bit IIS Agent, listening on http://amqa-clone73.test.forgerock.com:80
• Agent2 -> 32bit IIS Agent, listening on http://amqa-clone73.test.forgerock.com:81

Tests

OpenAM config:

• 1000 users (user.1 - user.1000)
• 2000 policies(agent:port/Resource1-1000.html)
• Each user can access only resource matching his number

Gatling:

• Flow:
  • Access protected resource
  • Expect redirect
  • Rest login
  • Access same resource in loop during 10 minutes

Observations:

When both agents are targeted at once (requests randomly go to 80 or 81), there is a significant slowdown (10x slower) compared to targeting single agent or non-protected resource. When this happen, CPU load on windows box goes down to ~10% utilization.

Tested also from two separated clients (2 gatling instances), each targeting single target.

NOTE: Retested also with 2x 64 bit application pool and results is the same.