On 11/9/2018 7:59 AM, Sankaranarayanan, Vignesh wrote:
> I guess you could say that it may need consideration when trying to push your 
> existing h/w to the limit, much like how WLM is to ration resources out when 
> things are running tight.
> – Vignesh

*Any*/every use of velocity needs *on-going* consideration.  It's a
completely arbitrary/mathematical construct that involves integer
division, so it has all the mathy issues that drags.  It was (is) simply
the least-bad *general* way to measure "progress" for things that don't
naturally complete transactions (servers, mostly).

Google around for papers with my name (it's pretty unique) and velocity;
I did one, probably at CMG, in 1995/1996 that still applies.  The only
"new" wrinkle is that the set of values feeding into the numerator and
denominator are a bit different now.  I/O was one of the changes (to
both); I don't remember the timing well enough to say whether I/O was
directly mentioned or just obliquely alluded to.

-- 
John Arwe
IBM Wave for z/VM Development product owner
former zWLM Head Bottlewasher & Jack of All Trades

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