Sorry, all the benchmarks were missing from my last comment.  Here they are:
                     total time          avg time/request     stddev
LEGACY_GIL
	serial
	((30, 500), (2.6908777512225717, 0.08968708313486773, 0.0015164644061278888))
	((300, 10), (0.4470272758129874, 0.0014862882945551276, 0.00024585959927491124))
	3.30s (3.14s)  [end-to-end time, ( sum of total times)
	simultaneous
	((30, 500), (2.876280574765787, 0.09586895587753937, 0.0011848842024515473))
	((300, 10), (3.2645357161315194, 0.010877886016239504, 0.027372366395914234))
	3.27s (6.14s)

LEGACY_GIL, affinity on
	serial
	((30, 500), (2.8003825905247735, 0.09333925587376796, 0.013360667457052446))
	((300, 10), (0.45636945477707364, 0.001517769716542185, 0.00020067298808990378))
	3.43s (3.26s)
	simultaneous
	((30, 500), (2.8963266281049687, 0.09653735553913509, 0.0096323348697044))
	((300, 10), (3.212417639672081, 0.010703065845891957, 0.014433573531885001))
	3.21s (6.11s)

ROUNDROBIN_GIL
	serial
	((30, 500), (2.703059536896449, 0.09009326837163198, 0.0020036630273102198))
	((300, 10), (0.4539455433581643, 0.0015096094615377107, 0.00041274624690973134))
	3.32s (3.16s)
	simultaneous
	((30, 500), (3.2613636649350686, 0.10870530565570016, 0.02613516235517462))
	((300, 10), (1.4737764855589188, 0.004908413639163637, 0.002818028070766402))
	3.26s (4.74s)

ROUNDROBIN_GIL, affinity on
	serial
	((30, 500), (2.7145072907310848, 0.09047581466359553, 0.0041867466462554535))
	((300, 10), (0.46542703053041656, 0.0015481250643121787, 0.0002282114778449236))

	3.36s (3.18s)
	simultaneous
	((30, 500), (2.8820070707310563, 0.09605833283280416, 0.004430198440914231))
	((300, 10), (3.2082978423235358, 0.010690429928943495, 0.014415958519681225))
	3.21s (6.09s)
	
ROUNDROBIN_GIL, USE_FIFO_COND
	serial
	((30, 500), (2.7050386292112547, 0.09016071176643957, 0.0017078174777967025))
	((300, 10), (0.4478294727402505, 0.001488698051474884, 0.00012887034661806298))
	3.31s (3.15s)
	simultaneous
	((30, 500), (3.262343957123042, 0.10873750248518549, 0.02640198429431565))
	((300, 10), (1.5242242379967286, 0.005076519036171731, 0.0033917786033315026))
	3.26s (4.79s)