Re: NetBSD speed curiosities

[Dave McGuire <mcguire%neurotica.com@localhost>]

On 04/16/2014 03:03 PM, John Klos wrote:
> I'm still puzzled by one thing that perhaps someone could explain. The
> Dhrystone benchmark from pkgsrc should be pretty consistent due to its
> simplicity. However, my 4000/30 (VLC) with NetBSD 6, which by many
> sources is supposed to be 5 VUPs or so, only reports 2109 runs per
> second, which is only about 1.2 times faster than the runs per second of
> an 11/780.
> 
> A 4000/60, which is supposed to be about 12 VUPs, gives 16305 runs/sec,
> which is about 9.2 times faster than an 11/780.
> 
> Why is this? Is there some issue which makes code too large to run
> inside of the CVAX SOC's 6k of cache? Is anyone running NetBSD 1.5 or
> another old version who could get some more numbers?

  I would immediately suspect caching issues here.  Have you looked at
the assembler output?

               -Dave

-- 
Dave McGuire, AK4HZ
New Kensington, PA