(Approximately the same question as I'm about to ask seems to have come up many times in -questions and -stable, but I haven't found a useful answer to it.)
I have a box running 6-STABLE, cvsupped yesterday. Until recently it was running 5.something and showed exactly the same peculiar behaviour as I'm about to describe. About 6 minutes after booting (on two occasions; I don't guarantee that this doesn't vary), a process that appears in the output of "ps" as "[swi4: clock sio]" begins to use about 3/4 of the machine's CPU. I think it does so more or less instantaneously. It continues to do so indefinitely, so far as I can tell. I'm not aware of anything specific that triggers this, though I suppose there must *be* something. It happens apparently spontaneously, on a lightly loaded machine. Those cycles are genuinely being consumed; other processes run much more slowly, and take much more wall time than CPU time. I've tried diddling my kernel's HZ value; the behaviour with HZ=100 and with HZ=1000 is the same, so far as I'm able to tell. I've no idea whether it might be relevant, but I have option DEVICE_POLLING turned on; toggling sysctl kern.polling.enable doesn't seem to make any difference. The machine is a very uninteresting single-CPU Athlon box, clocked at 1.6GHz, several years old. It used to run 4.x once upon a time, and I'm fairly sure it was fine then. As I mentioned above, it's running a recent 6-STABLE but showed the same pathology under 5.x. Here's its dmesg output, with a few uninteresting bits of information leakage elided. ---------- dmesg output begins ---------- Copyright (c) 1992-2006 The FreeBSD Project. Copyright (c) 1979, 1980, 1983, 1986, 1988, 1989, 1991, 1992, 1993, 1994 The Regents of the University of California. All rights reserved. FreeBSD 6.1-STABLE #3: Thu Jul 13 16:46:07 BST 2006 [EMAIL PROTECTED]:/usr/obj/usr/src/sys/xxxxxxxx ACPI APIC Table: <AMIINT VIA_K7 > Timecounter "i8254" frequency 1193182 Hz quality 0 CPU: AMD Athlon(tm) XP 1900+ (1599.73-MHz 686-class CPU) Origin = "AuthenticAMD" Id = 0x662 Stepping = 2 Features=0x383fbff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,PGE,MCA,CMOV,PAT,PSE36,MMX,FXSR,SSE> AMD Features=0xc0480800<SYSCALL,MP,MMX+,3DNow+,3DNow> real memory = 536805376 (511 MB) avail memory = 515944448 (492 MB) ioapic0 <Version 1.1> irqs 0-23 on motherboard netsmb_dev: loaded acpi0: <AMIINT VIA_K7> on motherboard acpi0: Power Button (fixed) Timecounter "ACPI-fast" frequency 3579545 Hz quality 1000 acpi_timer0: <24-bit timer at 3.579545MHz> port 0x808-0x80b on acpi0 cpu0: <ACPI CPU> on acpi0 acpi_throttle0: <ACPI CPU Throttling> on cpu0 acpi_button0: <Power Button> on acpi0 pcib0: <ACPI Host-PCI bridge> port 0xcf8-0xcff on acpi0 pci0: <ACPI PCI bus> on pcib0 agp0: <VIA 8367 (KT266/KY266x/KT333) host to PCI bridge> mem 0xe0000000-0xe3ffffff at device 0.0 on pci0 pcib1: <PCI-PCI bridge> at device 1.0 on pci0 pci1: <PCI bus> on pcib1 pci1: <display, VGA> at device 0.0 (no driver attached) xl0: <3Com 3c905C-TX Fast Etherlink XL> port 0xec00-0xec7f mem 0xdfffff80-0xdfffffff irq 17 at device 6.0 on pci0 miibus0: <MII bus> on xl0 ukphy0: <Generic IEEE 802.3u media interface> on miibus0 ukphy0: 10baseT, 10baseT-FDX, 100baseTX, 100baseTX-FDX, auto xl0: Ethernet address: 00:04:75:7e:54:fd isab0: <PCI-ISA bridge> at device 17.0 on pci0 isa0: <ISA bus> on isab0 atapci0: <VIA 8233 UDMA100 controller> port 0x1f0-0x1f7,0x3f6,0x170-0x177,0x376,0xfc00-0xfc0f at device 17.1 on pci0 ata0: <ATA channel 0> on atapci0 ata1: <ATA channel 1> on atapci0 uhci0: <VIA 83C572 USB controller> port 0xdc00-0xdc1f irq 5 at device 17.2 on pci0 uhci0: [GIANT-LOCKED] usb0: <VIA 83C572 USB controller> on uhci0 usb0: USB revision 1.0 uhub0: VIA UHCI root hub, class 9/0, rev 1.00/1.00, addr 1 uhub0: 2 ports with 2 removable, self powered uhci1: <VIA 83C572 USB controller> port 0xe000-0xe01f irq 5 at device 17.3 on pci0 uhci1: [GIANT-LOCKED] usb1: <VIA 83C572 USB controller> on uhci1 usb1: USB revision 1.0 uhub1: VIA UHCI root hub, class 9/0, rev 1.00/1.00, addr 1 uhub1: 2 ports with 2 removable, self powered uhci2: <VIA 83C572 USB controller> port 0xe400-0xe41f irq 5 at device 17.4 on pci0 uhci2: [GIANT-LOCKED] usb2: <VIA 83C572 USB controller> on uhci2 usb2: USB revision 1.0 uhub2: VIA UHCI root hub, class 9/0, rev 1.00/1.00, addr 1 uhub2: 2 ports with 2 removable, self powered pci0: <multimedia, audio> at device 17.5 (no driver attached) acpi_button1: <Sleep Button> on acpi0 fdc0: <floppy drive controller> port 0x3f2-0x3f3,0x3f4-0x3f5,0x3f7 irq 6 drq 2 on acpi0 fdc0: [FAST] fd0: <1440-KB 3.5" drive> on fdc0 drive 0 sio0: <16550A-compatible COM port> port 0x3f8-0x3ff irq 4 flags 0x10 on acpi0 sio0: type 16550A sio1: <16550A-compatible COM port> port 0x2f8-0x2ff irq 3 on acpi0 sio1: type 16550A ppc0: <ECP parallel printer port> port 0x378-0x37f,0x778-0x77b irq 7 drq 3 on acpi0 ppc0: SMC-like chipset (ECP/EPP/PS2/NIBBLE) in COMPATIBLE mode ppc0: FIFO with 16/16/9 bytes threshold ppbus0: <Parallel port bus> on ppc0 plip0: <PLIP network interface> on ppbus0 lpt0: <Printer> on ppbus0 lpt0: Interrupt-driven port ppi0: <Parallel I/O> on ppbus0 atkbdc0: <Keyboard controller (i8042)> port 0x60,0x64 irq 1 on acpi0 atkbd0: <AT Keyboard> irq 1 on atkbdc0 kbd0 at atkbd0 atkbd0: [GIANT-LOCKED] psm0: <PS/2 Mouse> irq 12 on atkbdc0 psm0: [GIANT-LOCKED] psm0: model Generic PS/2 mouse, device ID 0 pmtimer0 on isa0 sc0: <System console> at flags 0x100 on isa0 sc0: VGA <16 virtual consoles, flags=0x300> vga0: <Generic ISA VGA> at port 0x3c0-0x3df iomem 0xa0000-0xbffff on isa0 Timecounter "TSC" frequency 1599730245 Hz quality 800 Timecounters tick every 10.000 msec ad0: 38166MB <Seagate ST340014A 3.06> at ata0-master UDMA100 acd0: DVDROM <SAMSUNG DVD-ROM SD-616F/F101> at ata1-master UDMA33 Trying to mount root from ufs:/dev/ad0s1a ---------- dmesg output ends ---------- I would be grateful for any insight into what's going wrong and how (if at all) it can be fixed or worked around. I'm not subscribed to -questions or to -stable, so would prefer to be cc'ed, but I'll check the web archives and should therefore see any responses that go only to the list(s). Thanks in advance! -- Gareth McCaughan _______________________________________________ email@example.com mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "[EMAIL PROTECTED]"