Is it possible to implement a timeline semaphore with arbitrary payload value by any means? about vulkan-extensionlayer HOT 2 CLOSED

I don't think it would be possible to implement this reliably. Timeline semaphores are limited to increasing values to avoid race conditions between the signaller and the waiter. For example, if arbitrary values were allowed, you could signal 2, 4, 6, 5. Something waiting for 6 might wait forever because it might not 'see' the signal of 6 before 5 is signaled. If the value can only increase then waiting for >= 6 does not have a race condition. Your best bet is to restructure your code to fit with the limitations of timeline semaphores as they are defined in the spec. You may need to use more than one semaphore to achieve what you need.

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Thanks for your reply.
Some console platform implement this simply by a GPU label.
It is just a 4 or 8 bytes memory which will can be write and wait at proper pipeline stages end.
I just guess desktop GPUs should have such simple functionality.
But things seems not as easy as I think.

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