Re: "adapter resource shortage"?

["Michael L. Hitch" <mhitch%montana.edu@localhost>]

On Tue, 5 Mar 2013, Mouse wrote:

> I recently started trying to run a Sun Fire X4100, with amd64 5.2.
...
> sd1(mpt0:0:1:0): adapter resource shortage
>
> appearing once a second on the console (sd1 is the drive I was copying
> to, the one mounted -o async; the OS is on sd0).  These stopped when
> the transfer finished; when I told it to sync, in preparation for
> unmounting, they started again, and, watching the disk's busy light, I
> would estimate it is busy between 1/3 and 1/2 the time with a cycle
> time of about 1Hz, which is cripplingly inefficient.
>
> Reading the code leads me to suspect this is a perfectly normal
> resource shortage in the presence of more transfers pending than the
> hardware can handle.  However, arguing against this are (a) that
> someone felt that message worth printing and (b) that the recovery
> mechanism is a huge performance-killer, apparently locking up all
> transfers to that drive for an entire second.  (At least, that's what
> the code appears to be doing, and it matches well enough with the
> behaviour I saw.)

  This could be caused by the driver not reserving enough command slots 
for its internal use.  I committed a fix to reduce the maximum commands 
the scsipi layer would try to use (rev 1.17 of 
src/sys/dev/ic/mpt_netbsd.c, which should be in the 5.2 branch).  You 
might want to try reducing the scsipi openings a couple more and see if 
that helps.

Mike


---
Michael L. Hitch                        mhitch%montana.edu@localhost
Operations Consulting,  Information Technology Center
Montana State University, Bozeman, MT     USA