On Mon, Jan 12, 2004 at 11:11:28AM -0800, Brion Vibber wrote:
Ursula's sitting around with a 90% idle CPU, but
everything's blocked
on disk I/O to the point it's got a load average of about 16. At any
given time from 8-20 processes are blocked and waiting. Operations that
hit a lot of rows like history and watchlist are particularly badly hit
since they don't play as well with caching.
I mentioned this before, but it may have gotten lost as the server
fell over completely right afterwords...
Is DMA turned on and interrupt unmasking enabled on Ursula?
`/sbin/hdparm /dev/hda` (or whatever device it is) will show the
current configuration.
/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.
--
Audin Malmin - audin(a)okb-1.org
Every citizen should be a soldier. This was the case with the Greeks and
Romans, and must be that of every free state. -- Thomas Jefferson