numbers don't lie ...

[Michael Vince]

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?
>
>  
>
Even though your asking about user time I would like to point out I have 
long prefered to see build world as by far a hard disk io benchmark over 
a CPU benchmark.
After doing such benchmarks my self I have noticed my raid 1 SAS Dells 
with upto 40% less CPU power crush my Dell dual socket 3.6ghz raid 5 SAS 
servers in buildworld speed, this is purely because simple fact raid 5 
is much slower on writes, CPU has far less to do with buildworld 
performance.
Also a Dell 2950 on SATA seems to be a bit of a odd combination as I 
would believe most people get the SAS drives for a Dell 2950 and use the 
PERC5 / mfi SAS device crontroller.

Mike