[Info-vax] Performance benchmarks, was: Re: VMS Software Inc. OpenVMS 8.4-1H1 Boots on i4 System

[IanD]

On Thursday, March 19, 2015 at 7:52:50 PM UTC+11, Simon Clubley wrote:
> On 2015-03-19, David Froble <davef at tsoft-inc.com> wrote:
> > Simon Clubley wrote:
> >> 
> >> I'm not looking for something which is industrial strength, but rather
> >> a tool to get a quick feeling for relative performance between various
> >> hardware options.
> >> 
> >
> > Ah, yes, I think we can dig up something ..
> >
> >:-)
> >
> 
> [snip]
> 
> Thanks David, that's just the kind of thing I am looking for.
> 
> I'll give it a go when I get an Alpha emulator setup.
> 
> Simon.
> 
> -- 
> Simon Clubley, clubley at remove_me.eisner.decus.org-Earth.UFP
> Microsoft: Bringing you 1980s technology to a 21st century world

While I'm not at liberty to hand out the code (looks similar I think to the code posted further up the line) Stormasys do have code that is supposed to measure the performance, so you can compare the before and after when you move to an emulator. Maybe someone wants to ask them for it? I could dig it up but in fairness to them, I wouldn't release it unless it has their authority to do so plastered all over it

In our case, we ditched an 8400 and put in the equivalent emulated solution which simply flies (8 cpu's) running on a very high end proliant (the highest at the time before the current generation)

Another system we did 'virtualise' was an AlphaServer DS10L 67/616. The biggest gain by far was in the I/O

For the 8400 it made a reasonable difference (I don't have the data and it would take too much effort to dig it out of the archives, from memory things sped up by around 20 - 40%, don't quote me on that though) but the the DS10, we actually created an issue! (or uncovered one)

On the real DS10 we had 1 cpu and a bunch of slow disks. After the virtualisation was done, the system hit 100% cpu saturation on almost any job run! The I/O is so dam fast that unless you buy an excess of cpu's the quicker I/O will transfer over to a cpu very quickly. Due to licencing costs and the project closing, we are stuck with a cpu bottlenecked system now *sigh*

The new 8400 is in a cluster and even though we used flash memory for the disks on the 8400, the other member of the cluster is using SAN which now has become the I/O bottleneck where-as before it was the 8400 with it's slower SCSI local drives. I almost never see queued I/O's on the virtualised 8400 :-)

Sorry I don't have any figures to show but if you are going the emulator route and your doing a 1:1 replacement of cpu numbers, then pay particular attention to how your system may behave when the I/O throughput is increased orders of magnitude. A cpu bottleneck can very quickly materialise