Timekeeping hosed by factor 3, high lapic[01] interrupt rates

From: Jens Schweikhardt <schweikh_at_schweikhardt.net>
Date: Mon, 16 May 2005 13:34:20 +0200
hello, world\n

the timekeeping on my CURRENT system as of May 15 is very strange. The
time as reported by date(1) increases too slow by a factor of 3. Things
with second intervals like sleep 1, tail -f, iostat 1, changing folders
in mutt all go slower by a factor of 3.

The system bios date however is correct, and a kernel as of March does
not have this problem, so it's clearly the kernel or some other software
problem. I have investigated a bit and found the interrupt rates for the
lapic[01] being three times the value on the broken kernel (about 2kHz
vs 6kHz),

schweikh_at_hal9000:~ $ vmstat -i # Good kernel
interrupt                          total       rate
irq1: atkbd0                         250          0
irq3: sio1                             2          0
irq4: sio0                             2          0
irq12: psm0                         9079         25
irq13: npx0                            1          0
irq14: ata0                           84          0
irq15: ata1                           77          0
irq18: em0                          1091          3
irq24: ahd0                         9112         25
irq25: ahc0                           16          0
lapic0: timer                     722947       1997 <-- ~6057 on a bad system
irq0: clk                         361525        998
lapic1: timer                     708251       1956 <-- dito
Total                            1812437       5006 <-- greater than 12000

Maybe this gives someone a clue what goes on?

System is a supermicro P4SCT, 3GHz P4. Dmesg and kernel config upon request.

Regards,

	Jens
-- 
Jens Schweikhardt http://www.schweikhardt.net/
SIGSIG -- signature too long (core dumped)
Received on Mon May 16 2005 - 09:34:41 UTC

This archive was generated by hypermail 2.4.0 : Wed May 19 2021 - 11:38:34 UTC