I don't disagree with the idea of removing it, especially as it has so few users, but replacing the host lock with an atomic here would still vastly reduce the contention, which is the initial complaint. The
Actually the complaint is the overhead of the spin lock. This can be either caused
by contention or by cache line bounce time.
contention occurs because the host lock is so widely used for other things. The way to reduce that contention is firstly to reduce the length of code covered by the lock and also reduce the actual number of places where the lock is taken. Compared with host lock's current vast footprint, and atomic here is tiny.
That assumes that it's contention that is the problem and not simply bounce time.
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