I was thinking in regards to Sandy bridge having the uop queue laid out as 28-28, and with core parking enabled half the buffer goes unused.
I'm not sure why that would be the case. Core-parking deals with cores, and what you are talking about is intra-core.
I don't see how it would interact with core-parking unless logical cores were being "parked," which would mean that only hyper-threading Sandy Bridges would show any effect.
And, of course, if the logical cores are being parked, that would be an obvious performance difference by itself, right?
Ivy bridge/Haswell a single thread can use the whole 56 entry uop queue. With core parking enabled it should force the buffer from being partitioned into 28-28 hardwired split Sandy bridge has.
Are you saying that core parking makes Ivy Bridge/Haswell behave like Sandy Bridge? Because I don't think that's right, at all.