From: rick.c.hodgin@gmail.com   
      
   On Monday, March 11, 2019 at 5:41:04 AM UTC-4, wolfgang kern wrote:   
   > [Regarding RDTSCP]   
   >   
   > Yes, but only if more than one core is active.   
   > I mainly have just the boot-core active and make all others sleep.   
      
   RDTSCP is serializing.  It can affect real-world performance   
   comparisons in testing because of those side effects.   
      
   You'd be better off for benchmarking to set thread / process   
   affinity to a single core and use RDTSC.  Such an affinity   
   will keep data in the cache and present more realistic real-   
   world performance values.   
      
   You may also be better off for raw performance testing in   
   choosing a core not inundated with ISR handling and the like.   
      
   --   
   Rick C. Hodgin   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)