This leads me to wonder whether interrupt latency is getting to be
horribly long for some reason. It sounds like the requests are eventually
completing, but just taking lots longer than we expected.
A couple of thoughts - the timeout mechanism was never designed
with tagged queueing in mind. The clock starts when the request is first
passed down to the low-level driver, and the clock stops when the driver
reports that the request is done. Thus if the disk gets lots of requests
piled into it for some reason, and they are all large, the one at the end
will have to wait quite a bit before it gets processed.
I haven't been paying close attention - is it only the NCR and
Adaptec 2xxx series drivers that are showing this problem?
-Eric
-- "The woods are lovely, dark and deep. But I have promises to keep, And lines to code before I sleep, And lines to code before I sleep."