5.3-RELEASE: WARNING - WRITE_DMA interrupt timout - what does it mean?

[Robert Watson]

On Wed, 10 Nov 2004, Søren Schmidt wrote:

> > I'm still a bit skeptical that the task queue is at fault -- I run my
> > notebook with continuous measurement of the latency to schedule tasks,
> > generating a warning for any latency > .5 seconds, and the only time I
> > ever see that sort of latency is during the boot process when ACPI has
> > scheduled a task to run, but the task queue thread has not yet been
> > allowed to run:
> 
> Right, the timeout is 5 secs. I havn't looked into how the taskqueues
> are handled recently, but in case of ATA read/writes it is the
> bio_taskqueue handled by geom thats in use not the catchall ones, does
> your timing cover that as well? 

Nope -- I had assumed that the suggested task problems in question was the
use of taskqueue_enqueue() in ata-queue for the timeout, rather than the
bio_taskqueue() ata_completed() call.

Robert N M Watson             FreeBSD Core Team, TrustedBSD Projects
robert at fledge.watson.org      Principal Research Scientist, McAfee Research