A notable omission from the list of performance analysis tools has been
pointed out by a shy(?) denizen of info-WASD.  It *was* a product name that I
did recognise and I really should have included, "not a complete list I'm
sure", disclaimer with the article.

PERFDAT Data Collector
----------------------

  "VSI PERFDAT performance solution for OpenVMS addresses today’s OpenVMS
   customers’ most urgent performance management issues by providing an
   unprecedented level of insight into multi-system performance at low
   cost. A complete suite of highly automated collection, filtering,
   charting and trend analysis capabilities provides your IT staff with
   accurate and complete performance information for effective performance
   lifecycle management. PERFDAT is designed and developed for monitoring
   large complex OpenVMS environments and includes comprehensive data
   gathering, storage, and analysis functions. It also has the ability
   to monitor the performance of non-OpenVMS systems through
   standards-based extensions."

  https://vmssoftware.com/products/perfdat/

Absolutely sounds just the ticket when needing more than a snapshot.