>Number:         7687
>Category:       port-i386
>Synopsis:       1.4 + SCSI disk access = multi-second X delays?
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    port-i386-maintainer (NetBSD/i386 Portmaster)
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Tue Jun  1 18:20:00 1999
>Last-Modified:
>Originator:     Chris G. Demetriou
>Organization:
Chris Demetriou - cgd@netbsd.org - http://www.netbsd.org/People/Pages/cgd.html
Disclaimer: Not speaking for NetBSD, just expressing my own opinion.
>Release:        1.4
>Environment:
System: NetBSD 1.4 (SPEEDY) #18: Tue May 18 12:17:14 PDT 1999     cgd@speedy.int.demetriou.com:/a/users/cgd/proj/netbsd/src-1-4-branch/sys/arch/i386/compile/SPEEDY

>Description:
	I recently updated my home systems to NetBSD 1.4, and since
	the upgrade have noticed that moderate disk access (e.g. that
	generated by a single 'cvs update' running over a NetBSD source
	tree) is enough to cause X to freeze for a second or two at
	when cvs is thwacking the disk.  (By "thwacking" I mean the
	normal access that occur pretty much throughout a 'cvs -q update
	-Pd'.)  No other SCSI access-intensive processes are running at the
	same time, and the freezes do not appear to happen when not doing
	disk-intensive work.  (I've noticed similar problems when running
	large rm -rf's, as well.)

	dmesg output:

NetBSD 1.4 (SPEEDY) #18: Tue May 18 12:17:14 PDT 1999
    cgd@speedy.int.demetriou.com:/a/users/cgd/proj/netbsd/src-1-4-branch/sys/arc
h/i386/compile/SPEEDY
cpu0: family 6 model 1 step 9
cpu0: Intel Pentium Pro (686-class)
real mem  = 66715648
avail mem = 60104704
using 840 buffers containing 3440640 bytes of memory
mainbus0 (root)
pci0 at mainbus0 bus 0: configuration mode 1
pci0: i/o enabled, memory enabled
pchb0 at pci0 dev 0 function 0
pchb0: Intel 82441FX PCI and Memory Controller (PMC) (rev. 0x02)
pcib0 at pci0 dev 13 function 0
pcib0: Intel 82371SB PCI-to-ISA Bridge (PIIX3) (rev. 0x01)
pciide0 at pci0 dev 13 function 1: Intel 82371SB IDE Interface (PIIX3)
pciide0: bus-master DMA support present
pciide0: primary channel wired to compatibility mode
pciide0: disabling primary channel (no drives)
pciide0: secondary channel wired to compatibility mode
pciide0: secondary channel ignored (disabled)
uhci0 at pci0 dev 13 function 2: Intel 82371SB USB Host Controller (PIIX3) (rev.
 0x01)
uhci0: interrupting at irq 11
uhci0: USB version 1.0
usb0 at uhci0
uhub0 at usb0
uhub0: Intel UHCI root hub, class 9/0, rev 1.00/1.00, addr 1
uhub0: 2 ports with 2 removable, self powered
ppb0 at pci0 dev 14 function 0: Digital Equipment DECchip 21052 PCI-PCI Bridge (
rev. 0x01)
pci1 at ppb0 bus 1
pci1: i/o enabled, memory enabled
ex0 at pci1 dev 8 function 0: 3Com 3c905-TX 10/100 Ethernet
ex0: interrupting at irq 11
ex0: MAC address 00:c0:4f:b6:ec:30
nsphy0 at ex0 phy 24: DP83840 10/100 media interface, rev. 1
nsphy0: 10baseT, 10baseT-FDX, 100baseTX, 100baseTX-FDX, auto
vga1 at pci0 dev 16 function 0: Matrox MGA Millennium 2064W ("Storm") (rev. 0x01
)
wsdisplay0 at vga1: console (80x25, vt100 emulation)
ahc0 at pci0 dev 17 function 0
ahc0: interrupting at irq 11
ahc0: aic7880 Wide Channel, SCSI Id=7, 16 SCBs
scsibus0 at ahc0 channel 0: 16 targets, 8 luns per target
ahc0: target 0 using 16Bit transfers
ahc0: target 0 synchronous at 10.0MHz, offset = 0x8
sd0 at scsibus0 targ 0 lun 0: <SEAGATE, ST34371W, 0484> SCSI2 0/direct fixed
sd0: 4095MB, 5172 cyl, 10 head, 162 sec, 512 bytes/sect x 8388314 sectors
ahc0: target 5 synchronous at 10.0MHz, offset = 0xf
cd0 at scsibus0 targ 5 lun 0: <NEC, CD-ROM DRIVE:462, 1.14> SCSI2 5/cdrom remova
ble
ahc0: target 6 synchronous at 6.67MHz, offset = 0xf
st0 at scsibus0 targ 6 lun 0: <ARCHIVE, Python 00095-001, 5AB> SCSI2 1/sequentia
l removable
st0: drive empty
isa0 at pcib0
com0 at isa0 port 0x3f8-0x3ff irq 4: ns16550a, working fifo
com1 at isa0 port 0x2f8-0x2ff irq 3: ns16550a, working fifo
lpt0 at isa0 port 0x378-0x37b irq 7
sb0 at isa0 port 0x220-0x237 irq 5 drq 1 drq2 5: dsp v4.13
audio0 at sb0: full duplex
opl0 at sb0: model OPL3
midi0 at opl0: <SB Yamaha OPL3>
pckbc0 at isa0 port 0x60-0x64
pckbd0 at pckbc0 (kbd slot)
pckbc0: using irq 1 for kbd slot
wskbd0 at pckbd0: console keyboard
opms0 at pckbc0 (aux slot)
pckbc0: using irq 12 for aux slot
pcppi0 at isa0 port 0x61
sysbeep0 at pcppi0
isapnp0 at isa0 port 0x279: ISA Plug 'n Play device support
npx0 at isa0 port 0xf0-0xff: using exception 16
fdc0 at isa0 port 0x3f0-0x3f7 irq 6 drq 2
fd0 at fdc0 drive 0: 1.44MB, 80 cyl, 2 head, 18 sec
isapnp0: no ISA Plug 'n Play devices found
biomask 840 netmask 840 ttymask 18c2
wscons: wskbd0 glued to wsdisplay0 (console)

	The disk being accessed is the only disk on the system, sd0.

	X server: XF86_SVGA

	If any additional specific details are desired, please ask!

>How-To-Repeat:
	???  Possibly do some medium-strength disk bashing.

	If others are also seeing this problem, please reply to this
	PR with any additional details you can provide!

>Fix:
	???
>Audit-Trail:
>Unformatted: