From: d3@d3.d3   
      
   Hello...   
      
      
   More precision about the Microsoft windows futex..   
      
      
   Bonita Montero has just posted a simple benchmark that shows the   
   difference in speed between a windows futex and a spinlock in a   
   contention context with two threads, 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-wit   
   -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.   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)