How often does software actually ship with the opt in for segment heap turned on though ?

Anyway to globally turn it on when a blacklist or denylist or whatever in case something individual acts up ?

Not nearly often enough, because most veteran Windows deverlopers don't even know what segment heap is, or that they have a choice. VS code, for example, is still on NT Heap. It is heartbreaking how under-utilized and under-publicized segment heap is. Raymond Chen needs to make a public service announcement or something.

For the question of how to do "segment heap on globally, with a list of exceptions that are still on NT Heap", I believe the "Image File Execution Options" regkey takes precedence over the global one. And the IFEO one lets you explicitly opt out. If you read the whitepaper from Mark Yason's 2016 talk at black hat, they explain how to use these registry keys.

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Melatonic 4 days ago | parent [-]

Besides better ram utilisation is it offering actual performance improvements (regardless of ram availability) ? Need to read more about this

	▲	kh9000 4 days ago \| parent [-]
		In terms of speed, anecdotally, it seems like it can go either way. Some programs run faster, some run slower. Usage patterns of malloc/free are so varied that it's probably impossible to optimize for one without hurting others.