New != Faster

Tim Daneliuk tundra at tundraware.com
Mon Jun 4 17:54:27 UTC 2007


In the course of trying to work through some problems with a new MOBO,
I did some speed test which I found sort of surprising:

Old System
----------

Dual PIII 600Mhz w/768K Mem and Mylex RAID 5 with old 9G SCSI drived
FBSD 4.11-Stable
Writing a 1G file to /dev/null with dd reports about 26MB/sec

New System
----------

Pentium D 3.2GHz w/2G Mem and SATA Drive reported running at SATA-150
FBSD 6.2-STABLE
Writing a 2G file to /dev/null with dd reports about 50MB/sec


So ... the new system should be much faster all the way around, right?
Hmmmm, not necessarily so.  'buildworld' is only about 17% faster on the
new machine v. the old.  I would think that with way faster processors
and twice the disk bandwidth I would have seen far reduced buildworld
times.  So, I decided to check a known fast machine.  The results:

      Procs                     Mem     dd Read        OS            buildworld


Old   2 PIII @600Mhz           768K    26M/sec    4.11-stable/SMP    50-60 min
New   Pent D (2 core)@3.2GHz   2G     50M/sec    6.2-stable/SMP     40-50 min
Fast  2 Xeon @3GHz             3G    130M/sec    4.11-stable/SMP        8 min


So, now I'm confused.  These are all lightly loaded systems but the
buildworld time does not scale even approximately by either CPU or
I/O performance.  What the heck is going on, I wonder?  It is possible,
I suppose that the "New" machine does not have SMP running properly on it,
though 'top' shows two CPUs working away.  Is the difference in speed
attributable to 4.11 being faster than 6.2?  Unfortunately, I cannot
get 4.11 to boot on the "New" machine - it does not like the hardware
for some reason claiming:

     RTC BIOS diagnostic error 80<clock battery>

Even after I change the RTC battery on the mobo.

Strange ... any input appreciated.


-- 
----------------------------------------------------------------------------
Tim Daneliuk     tundra at tundraware.com
PGP Key:         http://www.tundraware.com/PGP/



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