There are several questions asking if disabling hyperthreading will improve performance (e.g. like [this](https://serverfault.com/questions/194377/will-disabling-hyperthreading-improve-performance-on-our-sql-server-install)). The answer (as it is to all performance questions) is of course "profile it on your workload".

As running experiments in a production environment is a poor idea (who wants to see reduced performance from an experiment in production!) and it isn't always feasible to set up a realistic development environment, I was wondering what measurements are available to determine if hyperthreading might be hurting performance (such that we only run an experiment that is likely to succeed!).

Notes:

1. This isn't an SQL specific question, I'm not looking for SQL statistics but rather performance counters from the operating system
2. The source code isn't available so no changes can be made there to monitor performance.