Date: Tue, 12 Nov 2002 13:31:35 -0300 From: Roberto de Iriarte <roberto@spock.cl> To: "Dr. Michael Mackey" <mackey@engineering.uiowa.edu> Cc: John Baldwin <jhb@FreeBSD.ORG>, freebsd-alpha@FreeBSD.ORG Subject: Re: Extreme time drift in SMP mode Message-ID: <3DD12CE7.10103@spock.cl> References: <XFMail.20021112104816.jhb@FreeBSD.org> <3DD12AA2.8D84B3E2@engineering.uiowa.edu>
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Dr. Michael Mackey wrote: >You're right, the clock on the Lynx (2100a) is an 8254: > >(from the output of dmesg) >FreeBSD 5.0-CURRENT #0: Mon Nov 11 15:31:50 CST 2002 > mackey@home.:/usr/src/sys/alpha/compile/HOME >Preloaded elf kernel "/boot/kernel/kernel" at 0xfffffc00006c2000. >DEC AlphaServer 2100A >AlphaServer 2100A 5/300, 291MHz >8192 byte page size, 2 processors. >CPU: EV5 (21164) major=5 minor=5 >OSF PAL rev: 0x4000100020116 >real memory = 199155712 (189 MB) >avail memory = 187490304 (178 MB) >FreeBSD/SMP: Multiprocessor System Detected: 2 CPUs >--- snip --- >Timecounters tick every 0.976 msec >Timecounter "i8254" frequency 1193182 Hz >--- snip --- > > >John Baldwin wrote: > > >>On 11-Nov-2002 Andrew Gallatin wrote: >> >> >>>Michael A. Mackey writes: >>> > It takes precisely twice as long (20 seconds) to run `sleep 10`. >>> > >>> > Why can't ntpd keep things in line? >>> > >>> >>>Because its not desgined to fix a clock which is that broken -- it >>>only increments a second or so at a time. Far too slow for your >>>purposes. >>> >>> >>So the clock is running at half-speed now? Hmm, the 2100[A] are >>Tincup, not Turbolaser, right? So it should be using the i8254 for >>its timecounter. Maybe the 8254 timecounter isn't setup right on >>the 2100a? >> >>-- >> >>John Baldwin <jhb@FreeBSD.org> <>< http://www.FreeBSD.org/~jhb/ >>"Power Users Use the Power to Serve!" - http://www.FreeBSD.org/ >> >> > > > Hmmm. my dmesg reads differently BTW, my system has only one CPU, and the clock has never drifted. ------------------------------------------------------------------------------------------------------------------------ FreeBSD 4.6.2-RELEASE #0: Thu Aug 22 20:40:14 GMT 2002 root@sema.baldwin.cx:/usr/src/sys/compile/GENERIC DEC AlphaServer 2100A AlphaServer 2100A 5/375, 374MHz 8192 byte page size, 1 processor. CPU: EV56 (21164A) major=7 minor=1 extensions=0x1<BWX> OSF PAL rev: 0x4000100020116 real memory = 1071570944 (1046456K bytes) avail memory = 1036902400 (1012600K bytes) Preloaded elf kernel "kernel" at 0xfffffc00007c6000. md0: Malloc disk t20: using interrupt type 1 on pci bus 0 pci0: <PCI bus> on pcib0 isab0: <Intel 82375EB PCI-EISA bridge> at device 2.0 on pci0 isa0: <ISA bus> on isab0 pcib1: <DEC 21050 PCI-PCI bridge> at device 3.0 on pci0 pci2: <PCI bus> on pcib1 sym0: <810a> port 0x5000-0x50ff mem 0x81040000-0x810400ff irq 28 at device 1.0 on pci2 sym0: No NVRAM, ID 7, Fast-10, SE, parity checking dc0: <Intel 21143 10/100BaseTX> port 0x5400-0x547f mem 0x81040100-0x8104017f irq 48 at device 6.0 on pci2 dc0: Ethernet address: 00:00:f8:1f:f6:2a miibus0: <MII bus> on dc0 dcphy0: <Intel 21143 NWAY media interface> on miibus0 dcphy0: 10baseT, 10baseT-FDX, 100baseTX, 100baseTX-FDX, auto mlx0: <Mylex version 2 RAID interface> port 0x10000-0x1007f irq 32 at device 6.0 on pci0 mlx0: DAC960P/PD, 1 channel, firmware 2.73-0-00, 16MB RAM mlxd0: <Mylex System Drive> on mlx0 mlxd0: 12042MB (24662016 sectors) RAID 5 (online) pci0: <unknown card> (vendor=0xff00, dev=0xff00) at 12.0 irq 1 pci0: <unknown card> (vendor=0x0000, dev=0x0000) at 12.4 pci0: <unknown card> (vendor=0xff00, dev=0xff00) at 13.0 irq 1 pci0: <unknown card> (vendor=0x0000, dev=0x0000) at 13.4 fdc0: <NEC 72065B or clone> at port 0x3f0-0x3f5,0x3f7 irq 6 drq 2 on isa0 fdc0: FIFO enabled, 8 bytes threshold fd0: <1440-KB 3.5" drive> on fdc0 drive 0 atkbdc0: <Keyboard controller (i8042)> at port 0x60,0x64 on isa0 atkbd0: <AT Keyboard> irq 1 on atkbdc0 mcclock0: <MC146818A real time clock> at port 0x70-0x71 on isa0 sio0: configured irq 4 not in bitmap of probed irqs 0x1 sio0 at port 0x3f8-0x3ff irq 4 on isa0 sio0: type 16550A, console sio1: reserved for low-level i/o ppc0: <Parallel port> at port 0x3bc-0x3c3 irq 7 on isa0 ppc0: Generic chipset (NIBBLE-only) in COMPATIBLE mode lpt0: <Printer> on ppbus0 lpt0: Polled port ppi0: <Parallel I/O> on ppbus0 Timecounter "alpha" frequency 374661324 Hz Waiting 15 seconds for SCSI devices to settle Mounting root from ufs:/dev/mlxd0a cd0 at sym0 bus 0 target 6 lun 0 cd0: <DEC RRD43 (C) DEC 1084> Removable CD-ROM SCSI-2 device cd0: 4.166MB/s transfers (4.166MHz, offset 8) cd0: cd present [384512 x 512 byte records] ------------------------------------------------------------------------------------------------------------------------------- As a matter of fact, there is no mention of an i8254 whatsoever. Should i source another CPU and try out 5.0 Current ? Regards, Roberto To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-alpha" in the body of the message
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