[Info-vax] Some VMS/x86 perf test data from WASD maintainer.

[David Jones]

On Sunday, April 30, 2023 at 12:42:06 AM UTC-4, Volker Halle wrote:
> David Jones schrieb am Samstag, 29. April 2023 um 21:56:27 UTC+2: 
> 
> thanks for this experiment. It shows the current huge overhead, when introducing kernel mode calls. Let's be fair: VSI is still concentrating on functionality vs. performance for OpenVMS x86-64. So we should wait for the native build of the OS - as indicated by Rob. 
> 

Since this application only expects a handful of threads, I implemented a user-mode replacement
for pthread_getspecific(). So now, using 2 threads completes the run in 65% of the wall clock
time as the single thread case (with process being charged 130% the CPU time). Using 4 threads
completes in 35% the wall clock time (40% CPU overhead). I don't know if the 40% is scheduler
overheader or memory bus contention or perhaps the power management hardware is varying
the clock speed when 4 cores become active on the laptop.