numbers don't lie ...

[Pieter de Goeje]

On Wednesday 13 September 2006 08:36, Danny Braniss wrote:
> Im testing these 2 boxes, Sun X4100 and Dell-2950, and:
>
> 	SUN X4100:	Dual Core AMD Opteron(tm) Processor 280 (2393.19-MHz K8-class
> CPU) one 70g sata disk
> 	DELL 2950:	Intel(R) Xeon(TM) CPU 3.20GHz (3192.98-MHz K8-class CPU)
> 			4 sata disks + raid0
>
> they both run identical 6.1-STABLE.
>
> my 'cpu benchmark' shows the amd being much better than the intel.
> but, doing a make buildworld give interesting results:
>
> dell-2950 : make -j16 TARGET_ARCH=amd64 buildworld : 24m17.41s real
> 1h3m3.26s user 17m15.07s sys
> dell-2950 : make -j8 TARGET_ARCH=amd64 buildworld : 24m8.28s real
> 1h2m59.38s user 16m16.20s sys
>
> sunfire : make -j16 TARGET_ARCH=amd64 buildworld : 24m21.38s real 49m6.68s
> user 14m22.64s sys
> sunfire : make -j8 TARGET_ARCH=amd64 buildworld : 23m47.69s real 48m53.58s
> user 13m44.81s sys
>
> which probably says something about my 'cpu benchmark' :-(
> but why is the user time so much different between the boxes?

Maybe the sunfire's CPU is faster, but has to wait on the harddisk. The 
buildworld 'benchmark' is probably for a large part I/O bound.

- Pieter de Goeje