Date: Wed, 20 Sep 2006 15:08:35 +1000 From: Michael Vince <mv@thebeastie.org> To: Danny Braniss <danny@cs.huji.ac.il> Cc: freebsd-hackers@freebsd.org Subject: Re: numbers don't lie ... Message-ID: <4510CCD3.5060000@thebeastie.org> In-Reply-To: <E1GNOLq-000DC2-1Q@cs1.cs.huji.ac.il> References: <E1GNOLq-000DC2-1Q@cs1.cs.huji.ac.il>
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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
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