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0 pointsconradludgate1y ago0 comments

Benchmarks will always look good when using a spin-lock like you seem to be using here https://github.com/fortress-build/whirlwind/blob/0e4ae5a2aba...

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dwattttt1y ago· 2 in thread

I believe that doesn't indicate it's spinlocking; the `poll` API is specified to not block.

conradludgateOP1y ago

> In software engineering, a spinlock is a lock that causes a thread trying to acquire it to simply wait in a loop ("spin") while repeatedly checking whether the lock is available

Immediately waking itself, the task is scheduled and will be polled again shortly. This creates the loop in which is checks if the lock is available. This has no effective difference compared to using hint::spin_loop() but in async.

A more traditional lock will use a queue in which the task will not be polled until it's likely available, rather than blindly trying on repeat.

dwattttt1y ago

The code linked does the following:

- attempt to acquire an RWLock without blocking

- if it does, wake the task waiting for the lock

- if it doesn't, return "not ready yet"

The RWLock is straight from the standard lib; there's no loop and no spinning involved. Every single Future you look at will look like this, by specification they cannot block, only return "ready" (and wake the task), or return "not ready".

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