Roy Sigurd Karlsbakk wrote:
>
> > What chipset is the motherboard? And do you have IO-APIC enabled? See if
> > irq's appear under both cpu's in /proc/interrupts...if they are spread
> > out on both cpu's it is enabled.
>
> Chipset:
> Host bridge: ServerWorks CNB20HE + +
Known for 64 bit bus.
> PCI Bridge Intel 80960 RP
>
> Interrupts:
> CPU0 CPU1
> 0: 37553 37575 IO-APIC-edge timer
> 1: 674 624 IO-APIC-edge keyboard
> 2: 0 0 XT-PIC cascade
> 5: 109107 106066 IO-APIC-level cciss0
> 9: 0 0 IO-APIC-level acpi
> 11: 969 967 IO-APIC-level e1000
> 12: 14 21 IO-APIC-edge PS/2 Mouse
> 15: 1 0 IO-APIC-level cpqphp.o
> NMI: 0 0
> LOC: 75032 75031
> ERR: 0
> MIS: 0
APIC is definitely enabled.
>
> > Now you mention a high memory bandwidth, but is this still a standard
> > PCI slot (thus 33 MHz/32 bit)? If so, it'd be kind of like putting a
> > fast AGP graphics card in an ordinary PCI slot...it would be a
> > bottleneck between the higher bandwidth and the card.
>
> It's using two sdram dimms in parallel on the memory bus. It's got one
> 33/32 PCI bus, one 33/64, and one 66/64 bus. I really can't find any
> bottleneck apart from the disks seeking like idiots.
It isn't unusual for any of these busses to try and autosense if
standard 32 bit/33 MHz cards are in a slot, and scale back the speed of
the entire bus to 33 MHz for anything on it. This certainly has the
ability to pump out a lot of bandwidth on any U160 or RAID controller,
probably the only thing I'd want to double check on is if a slower card
is cutting the whole bus back (I'm guessing dmesg startup will give that
information, but I'm not positive).
Now if these disks are thrashing around a lot, it seems that something
else must be going on. Have you tried checking performance and thrashing
behavior if the disks are formatted and used separately, versus some
form of RAID or logical volume management? I'm also curious what the
chunk size is? (chunk size != block size). If chunk size is too small,
it might cause thrashing. If it is rather large, you won't really be
splitting writes and reads across multiple striped disks, it'd be a
series of small writes alternating between disks in that case.
D. Stimits, stimits@xxxxxxxxxx
>
> >
> > D. Stimits, stimits@xxxxxxxxxx
> >
> > >
> > > --
> > > Roy Sigurd Karlsbakk, MCSE, MCNE, CLS, LCA
> > >
> > > Computers are like air conditioners.
> > > They stop working when you open Windows.
> >
>
> --
> Roy Sigurd Karlsbakk, MCSE, MCNE, CLS, LCA
>
> Computers are like air conditioners.
> They stop working when you open Windows.
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