About the Mircosoft windows futex..

[Amine Moulay Ramdane]

Hello,


About the Mircrosoft windows futex..

Bonita Montero has just posted a simple benchmark that shows the difference in speed between a windows futex and a spinlock, and here is my
conclusion:

I think i can logically infer the following from the benchmark,

Since the benchmark is giving 6x times more speed to the spinlock than
to the windows futex, so i think that the windows futex is still doing a system call directly without spinning so that to reduce the system calls that are expensive and so that to avoid convoying, this is why i think the windows futex is still slow and it is not good.

And since the windows futex is not reducing the system calls, here is
another problem with the system calls of the windows futex:

System calls have become more expensive with Meltdown

Read more here:

https://hackernoon.com/system-calls-have-been-more-expensive-with-meltdown-how-to-avoid-them-af4b0026d35a

Note: Futexes have been implemented in Microsoft Windows since Windows 8 or Windows Server 2012 under the name WaitOnAddress.

Thank you,
Amine Moulay Ramdane.