So far my test instances with one or both of the MWAIT-related kernel flags have given even worse results than the original: They boot showing intel_idle disabled on E5410 nodes only, but the (assumed) E5506 nodes just terminate themselves quickly with no console log output at all (even after waiting a while). I've opened a web support ticket with Amazon referencing my test AMI and this bug report to ask for their input.
So far my test instances with one or both of the MWAIT-related kernel flags have given even worse results than the original: They boot showing intel_idle disabled on E5410 nodes only, but the (assumed) E5506 nodes just terminate themselves quickly with no console log output at all (even after waiting a while). I've opened a web support ticket with Amazon referencing my test AMI and this bug report to ask for their input.