When booting my new Dell 4400, pre-installed with Red Hat 6.1, the
raid5 checksumming function it chooses is not the fastest. I get:
raid5: measuring checksumming speed
raid5: KNI detected,...
pIII_kni: 1078.611 MB/sec
raid5: MMX detected,...
pII_mmx : 1304.925
p5_mmx : 1381.125
8 regs : 1029.081
32 regs : 584.073
using fastest function: pIII_kni (1078.611 MB/sec)
Is there a good reason for it choosing pIII_kni (in which case the
wording of the message "fastest" needs changing) or is it a bug? If
noone else sees this, I'll dig in and see if I can fix it: maybe
it's because the two sets of function lists are dependent on
particular hardware (first for KNI, then for MMX) and something isn't
getting zeroed or set to the max in between.
Benchmarking it on a stripeset of 7 x 9GB disks on a Ultra3 bus with
one of the Adaptec 7899 channels, it's impressively fast. 81MB/s block
reads and 512 seeks/s in bonnie and 50MB/s (500 "netbench" Mbits/sec)
running dbench with 128 threads. I've done tiotest runs too and I'll
be doing more benchmarks on RAID5 soon. If anyone wants me to post
figures, I'll do so.
--Malcolm
--
Malcolm Beattie <[EMAIL PROTECTED]>
Unix Systems Programmer
Oxford University Computing Services
