Blocked state from nsight system report

Can someone explain to me what might be the causes of blocked states reported by nsight system?

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I am sorry that there was no response to this earlier, your forum post was dropped in an orphaned category that the Nsys team was unaware of until this afternoon.

The blocked state corresponds to a place in the timeline where the OS was keeping the CPU from being active. This could be something like waiting for a barrier/mutex. If you zoom in/hover over the blocked state, you will see a tooltip that will indicate what the OS call was and the stack trace that got you there.