The following reply was made to PR port-i386/33585; it has been noted by GNATS.

From: Manuel Bouyer <bouyer@antioche.eu.org>
To: gnats-bugs@NetBSD.org
Cc: port-i386-maintainer@NetBSD.org, gnats-admin@NetBSD.org,
	netbsd-bugs@NetBSD.org
Subject: Re: port-i386/33585: piixide interrupt thrashing on SATA interface
Date: Thu, 1 Jun 2006 13:13:02 +0200

 On Mon, May 29, 2006 at 08:40:00AM +0000, abrasive@axdf.net wrote:
 > >Number:         33585
 > >Category:       port-i386
 > >Synopsis:       Heavy SATA disk load causes huge interrupt load (piixide)
 > >Confidential:   no
 > >Severity:       serious
 > >Priority:       medium
 > >Responsible:    port-i386-maintainer
 > >State:          open
 > >Class:          support
 > >Submitter-Id:   net
 > >Arrival-Date:   Mon May 29 08:40:00 +0000 2006
 > >Originator:     James Laird
 > >Release:        NetBSD 3.0
 > >Organization:
 > 	AXDF
 > >Environment:
 > System: NetBSD what-are-birds 3.0 NetBSD 3.0 (BIRDS.PROF) #0: Tue May 30 02:29:48 EST 2006 root@what-are-birds:/usr/src/sys/arch/i386/compile/BIRDS.PROF i386
 > Architecture: i386
 > Machine: i386
 > >Description:
 > 	Whenever SATA disk is heavily loaded (e.g. making filesystems) the CPU interrupt time climbs to 60-80% (Intel P4 2.8Ghz).
 > 	vmstat -i shows an interrupt rate on the appropriate ioapic pin in the region of 1-2 thousand per second with disk load, and less than 100 with no load.
 
 How many disk transfers per second is there ? With the current driver you
 have one interrupt per transfers, and with modern disk with large write-back
 cache we can certainly get that much I/O per second.
 
 'systat vm' will show you these informations (both interrupt rate and I/O rate)
 
 -- 
 Manuel Bouyer <bouyer@antioche.eu.org>
      NetBSD: 26 ans d'experience feront toujours la difference
 --