Date: Thu, 21 Jun 2001 14:39:09 +0200 (CEST) From: Martin Blapp <mb@imp.ch> To: <smp@FreeBSD.org> Subject: RE: clock speedup on SMP boxes Message-ID: <20010621143000.I766-100000@levais.imp.ch>
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Hi,
We have seen this timedrifting here too on a 4.3 RELEASE. We have some
busy SMP mysql servers, and from time to time a mysql prozess hangs
get stuck in poll() and gettimeofday(). With a normal for loop, or a busy
system we do not see a noticable time drifting, but if we start this
(below attached) little program here, we see a severe time drifting, the
clock runs much faster !
Our servers here are big SMP servers from Siemens.
Here is some dmesg output:
Timecounter "i8254" frequency 1193182 Hz
CPU: Pentium III/Pentium III Xeon/Celeron (933.37-MHz 686-class CPU)
Origin = "GenuineIntel" Id = 0x686 Stepping = 6
Features=0x383fbff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,PGE,MCA,CMOV,PAT,PSE36,MMX,FXSR,SSE>
real memory = 1073721344 (1048556K bytes)
avail memory = 1040846848 (1016452K bytes)
Changing APIC ID for IO APIC #1 from 3 to 1 in MP table
Changing APIC ID for IO APIC #1 from 3 to 1 on chip
Programming 16 pins in IOAPIC #0
IOAPIC #0 intpin 2 -> irq 0
Programming 16 pins in IOAPIC #1
FreeBSD/SMP: Multiprocessor motherboard
cpu0 (BSP): apic id: 3, version: 0x00040011, at 0xfee00000
cpu1 (AP): apic id: 0, version: 0x00040011, at 0xfee00000
io0 (APIC): apic id: 2, version: 0x000f0011, at 0xfec00000
io1 (APIC): apic id: 1, version: 0x000f0011, at 0xfec01000
IOAPIC #1 intpin 4 -> irq 2
IOAPIC #1 intpin 2 -> irq 10
APIC_IO: Testing 8254 interrupt delivery
APIC_IO: Broken MP table detected: 8254 is not connected to IOAPIC #0
intpin 2
APIC_IO: routing 8254 via 8259 and IOAPIC #0 intpin 0
And here the test programm which produces the time drifting.
#include <sys/types.h>
#include <sys/time.h>
#include <err.h>
#include <fcntl.h>
#include <poll.h>
#define DATA "/dev/zero"
int
main(void)
{
int fd;
struct pollfd pfd;
fd = open(DATA, O_RDONLY);
if(fd < 0) {
err(1, "open()");
}
for(;;) {
int nfds;
struct timeval tv;
struct timezone tz;
pfd.fd = fd;
pfd.events = POLLRDNORM;
pfd.revents = 0;
nfds = poll(&pfd, 1, 0);
gettimeofday(&tv, &tz);
}
return (0);
}
Martin Blapp, mb@imp.ch
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