[Info-vax] High resolution per-process CPU consumption statistics

[Bob Gezelter]

On Monday, March 23, 2020 at 8:02:22 PM UTC-4, Mark Daniel wrote:
> Would like to be able to measure process CPU consumed during specified 
> continuous sections of processing.  Only interested in CPU-intensive 
> sections so USER mode consumed relevant.  Imagine inserting calls at the 
> beginning and ending of those sections with a magic number representing 
> CPU consumption/delta/whatever made available.
> 
> As some of these CPU-intensive code sections are short duration the 
> granularity needs to be quite fine.  The likes of JPI$_CPUTIM and 
> LIB$STAT_TIMER (10mS) seem unsuitable.
> 
> Prepared for non- USER mode code.  This is only for ad hoc developmental 
> insight and not general use.  Needs to accommodate Alpha and/or Itanium 
> (and/or x86-64 :-)
> 
> And, of course, any other suggestion.
> 
> As always, TIA.

Mark,

SYS$GETTIME_PREC will get you the full precision of the system clock on Itanium.  Unfortunately, this is elapsed time, not CPU time. One has to be careful, but it gives a upper bound on the lower bound of how long a compute section takes (because of irreproducible interference effects).

GETJPI is documented as limited to 10 ms tics.

- Bob Gezelter, http://www.rlgsc.com