[Info-vax] VUPS.COM relevance for modern CPUs

[abrsvc]

On Monday, December 19, 2022 at 8:23:23 AM UTC-5, Simon Clubley wrote:
> On 2022-12-19, Mark Daniel <mark.... at wasd.vsm.com.au> wrote: 
> > 
> > With this in mind I knocked-up a small program to repeatedly call a 
> > function using $CMEXEC which calls a function using $CMKRNL and that is 
> > that. It measures how much effort is required compared to the simple 
> > USER mode loop and reports it as b[ogo]VUPs. 
> > 
> > https://wasd.vsm.com.au/wasd_tmp/bogovups.c 
> > 
> > The real disappointment is my X86 VM. The rest of the results seem in 
> > line with expectations. 
> >
> What numbers did you see ?
> > PS. Looking for ideas, suggestions, criticism(s), etc. here... 
> >
> The tests still "feel" rather artificial. 
> 
> My suggested alternative would be to write actual files away to disk 
> using RMS sequential files and also indexed files. Maybe read them 
> back as well. 
> 
> Repeat the sequential files test using direct QIO access and see what 
> performance difference that gives when you bypass the transition to 
> executive mode. 
> 
> (Yes, I know, RMS will add its own fixed overheads, but you will still 
> be able to see a percentage difference across the various machines you 
> are testing on and whether x86-64 VMS imposes a much higher performance 
> overhead.) 
> 
> One obvious problem is that you will have to address issues round 
> caching in your tests.
> Simon. 
> 
> -- 
> Simon Clubley, clubley at remove_me.eisner.decus.org-Earth.UFP 
> Walking destinations on a map are further away than they appear.
Why would you want I/O involved in a measurement of relative CPU power?  That makes no sense.  The VUPs rating has always been a relative CPU performance test.  You can argue whether User mode vs other modes makes sense.  I suppose that using Mark's updated program may make sense given that the newer versions of OpenVMS use software for some functions (modes really).  I don't believe that this is accurate as it will compare hardware vs software between a few models.

I would be interested in (and will likely test) this new option in the emulated environment.  It may be a more consistent comparison in this environment.

Dan