On Jan 12, 2004, at 11:22, audin(a)okb-1.org wrote:
Is DMA turned on and interrupt unmasking enabled on
Ursula?
DMA is on. Interrupt unmasking, no.
`/sbin/hdparm /dev/hda` (or whatever device it is)
will show the
current configuration.
# /sbin/hdparm /dev/hda
/dev/hda:
multcount = 16 (on)
IO_support = 0 (default 16-bit)
unmaskirq = 0 (off)
using_dma = 1 (on)
keepsettings = 0 (off)
readonly = 0 (off)
readahead = 8 (on)
geometry = 7476/255/63, sectors = 120103200, start = 0
/sbin/hdparm -u1 -c3 -d1 /dev/hda` will turn on DMA,
turn off
interrupt masking, and enable 32bit i/o support. Interrupt masking
itself can
have a huge impact on the amount of cpu time spent waiting for the
disk...and
it is almost always set conservatively (ie: wrong) on an untweaked
linux
installation.
Well, went ahead and turned on interrupt unmasking and 32-bit io. The
numbers in vmstat don't look too much different yet, but we'll see.
-- brion vibber (brion @
pobox.com)