Re: [Xenomai-core] bad/slow TSC hw detected by 2.6.17-rc1-mm1

2006-04-10 Thread Jim Cromie 

Jan Kiszka wrote:

Jim Cromie wrote:
  

FYI,

Ive just built 17-rc1-mm1, and noted that the new time-keeping-system
http://lwn.net/Articles/176837/

can now detect the buggy TSC on my GEODE-sc1100 cpu,
and also that its apparently fixable by adding 'idle=poll' to
kernel-boot-line.



Keeps your CPU safe and warm, I guess. ;)

  
for me personally, its the new-found certainty that the bug is 
repeatedly observable and correctable :-)


Ive historically had an issue with  my ntp-server on this box,
which slips badly when running latency tests under certain conditions
(ie, the dd workload is using /dev/hda, a real interrupt source, rather 
than /dev/zero)


FWIW, my 2.6.16-ipipe-122 kernel takes a *long* time to boot,
even while printk numbers look good.

The delays/pauses are in several subsystems, most notably after these 
dmesg lines:


[   30.768098] Uniform Multi-Platform E-IDE driver Revision: 7.00alpha2
[   30.775141] ide: Assuming 33MHz system bus speed for PIO modes; 
override with idebus=xx


(1 min pause)

[   31.209246] hda: SanDisk SDCFB-512, CFA DISK drive

[   30.561093] Serial: 8250/16550 driver $Revision: 1.90 $ 4 ports, IRQ 
sharing disabled


30.574876] serial8250: ttyS0 at I/O 0x3f8 (irq = 4) is a 16550A
[   30.586719] serial8250: ttyS1 at I/O 0x2f8 (irq = 3) is a 16550A

(more delays, in various spots, and Im now much more aware of them..)

FWIW, before now, Ive never needed idle=poll, so it seems that 
adeos/xenomai

is more sensitive to these long delays than vanilla linux,  (same for more
recent versions of kernel  adeos).  OTOH, Ive only recently added 
timestamps to

printks, and Im also a bit more sensitive now than I once was ..


Does it make any sense that adeos / xenomai is more sensitive to a bad TSC
than it used to be ?

thanks
jimc

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Re: [Xenomai-core] bad/slow TSC hw detected by 2.6.17-rc1-mm1

2006-04-08 Thread Jan Kiszka 
Jim Cromie wrote:
 FYI,
 
 Ive just built 17-rc1-mm1, and noted that the new time-keeping-system
 http://lwn.net/Articles/176837/
 
 can now detect the buggy TSC on my GEODE-sc1100 cpu,
 and also that its apparently fixable by adding 'idle=poll' to
 kernel-boot-line.

Keeps your CPU safe and warm, I guess. ;)

 
 Apr  7 11:42:01 truck kernel: [   19.160016] Kernel command line:
 console=ttyS0,115200n81 root=/dev/nfs
 nfsroot=192.168.42.1:/nfshost/truck
 nfsaddrs=192.168.42.100:192.168.42.1:192.168.42.1:255.255.255.0:soekris:eth0
 panic=5 initrd=initrd-2.6.17-rc1-mm1-sk.img 
 BOOT_IMAGE=vmlinuz-2.6.17-rc1-mm1-sk
 Apr  7 11:42:01 truck kernel: [   24.314851] Time: tsc clocksource has
 been installed.
 Apr  7 11:42:01 truck kernel: [   29.977802] TSC appears to be running
 slowly. Marking it as unstable
 Apr  7 11:42:01 truck kernel: [   20.46] Time: pit clocksource has
 been installed.
 
 Apr  7 12:35:56 truck kernel: [   21.562573] Kernel command line:
 console=ttyS0,115200n81 root=/dev/nfs
 nfsroot=192.168.42.1:/nfshost/truck
 nfsaddrs=192.168.42.100:192.168.42.1:192.168.42.1:255.255.255.0:soekris:eth0
 panic=5 initrd=initrd-2.6.17-rc1-mm1-sk.img idle=poll
 BOOT_IMAGE=vmlinuz-2.6.17-rc1-mm1-sk
 Apr  7 12:35:56 truck kernel: [   21.563049] using polling idle threads.
 Apr  7 12:35:56 truck kernel: [   28.393469] Time: tsc clocksource has
 been installed.
 
 
 hope this is useful,
 jimc
 

Jan



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