[Info-vax] Autogen

[Stephen Hoffman]

On 2018-02-01 16:34:06 +0000, Marc Van Dyck said:

> So my question : is this procedure still uptodate ? Has it been 
> modified to take in account the much larger memory capacities that we 
> can see today (our production systems have 192 GB) ? Can we still trust 
> the 'optimal' parameter values that it computes ? And should we still 
> autogen with feedback systems as often as we did in the past ?

It does what it says on the tin, if that's what you're asking.   Some 
of the traditional system parameters were effectively and quietly 
deprecated a while back; they're still around, but have been set to 
their maximal values or to "magic" values, indicating the use of the 
maximal architectural settings.  There are probably some others that 
could see similar deprecations, too.   AUTOGEN itself definitely does 
need UI work, not the least of which would be the addition of numeric 
formatting (comma or dot separators) in the displays of larger values.  
Probably also needs a rework or a rewrite to integrate with some future 
follow-on to T4 and trends for data collection and reporting, and with 
reporting as trends head toward limits.  Not sure I'd expect to see ML 
added here, but that'd certainly be a longer-term research area.  Make 
the basic tuning and reporting happen automatically, when that's not 
been explicitly disabled.  As for your question, look at your apps, and 
see what the usage and trends are for those.  T4 data helps, there.   
AUTOGEN and parameters and system-level tuning is a blunt instrument.  
So too is a hardware upgrade or server replacement, but hardware can 
tend to be less expensive than app software fixes; app algorithm 
changes.  Tuning also doesn't get you very much past the first or 
second tuning pass for a given environment and given load, outside of 
what would be fairly egregious parameter settings.   But yes, AUTOGEN 
still does what it does.  I'd centrally watch the T4 data or 
equivalent, and the trends with the apps, and would seriously consider 
adding local- or app-level collection of performance data in critical 
apps, though.  OpenVMS doesn't have built-in features akin to dtrace or 
instruments to assist with monitoring app activity, which means the 
process and the data collection can often be bespoke.  Though 
definitely T4 helps.


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