Subject: Re: kern/8217: periodic pciide pauses?
To: None <,>
From: Manuel Bouyer <>
List: netbsd-bugs
Date: 08/23/1999 18:30:58
On Wed, Aug 18, 1999 at 10:12:42AM +0300, Antti Kantee wrote:
> On Tue Aug 17 1999 at 21:53:13 +0000, Matthias Scheler wrote:
> > > During periods of heavy disk i/o to UDMA pciide drives, programs will
> > > periodically "freeze" for up to about 5 seconds and then start up
> > > again.
> > 
> > A few seconds ago I experienced this problem with a SCSI disk, too. It
> > happened while extracting a "tar" archive from a NFS filesystem to a
> > local filesystem on an UW SCSI disk. So it's obviously not related to
> > the PCI IDE driver.
> > 
> > I suppose it is more related to buffer management because all affected
> > boxes have lots of memory (either 128 or 256MB).
> I remember getting it on a 32MB box when I was using wdc, so I guess it
> wouldn't be directly related to either of the above causes.

I guess this depend on the ratio between the buffer cache and the drive
speed, if the abobe theory is correct.

I noticed these hangs with large (20Mb) buffer caches too, on both IDE and
SCSI disks. I proved they are related to sync(2) in my case (killing update
and running sync(8) manually).
Maybe there's 2 different bugs ?

Manuel Bouyer, LIP6, Universite Paris VI.