Re: kern/41417 (WAPBL: hang on tstile)

[David Holland <dholland-bugs%netbsd.org@localhost>]

The following reply was made to PR kern/41417; it has been noted by GNATS.

From: David Holland <dholland-bugs%netbsd.org@localhost>
To: gnats-bugs%NetBSD.org@localhost
Cc: 
Subject: Re: kern/41417 (WAPBL: hang on tstile)
Date: Wed, 27 Jul 2011 15:58:01 +0000

 On Wed, Jul 27, 2011 at 03:45:02PM +0000, Manuel Bouyer wrote:
  >  Hum, but the rsync is very slow with a current kernel, so the problem
  >  may well have been hidden by this slowness.
 
 I saw when pounding on it that from time to time the whole thing would
 stop for a while, then (maybe after a timeout somewhere) would resume
 again.
 
 I'm pretty sure that isn't either anything I did or a locking issue;
 hangs from locking issues tend to be permanent.
 
  >  Select blocks, and returns after the timeout period, while there is data
  >  ready to be read. The next select call returns immediatly. Did something
  >  change in this area recently ?
 
 Possibly; I'm not sure.
 
 Another candidate is the weird raidframe throughput problems mrg was
 seeing and possibly also some of the NFS hangs I was seeing a few
 weeks ago(*); and maybe some other related phenomena that have been
 reported. It looks as if maybe there's a problem where under some
 circumstances callouts stop getting processed... I think there's
 discussion on tech-kern and it's probably best to look there.
 
 -- 
 David A. Holland
 dholland%netbsd.org@localhost